Hector's Airgun Blog

FT rifles for small frame shooters

10/29/2023

It all started with Izaak Walton-Wildlife Achievement Chapter (WAC)/DIFTA

Every good story has a beginning.
You could argue that DIFTA's FT range is the OLDEST FT range in CONTINUOUS use. Per the Club's recorded history, the first formal FT Match was held there in March 1998.
Since then, the location has not changed in over 25 years.
Sure improvements have been made! there is a dedicated, covered, 55 yards airgun range with a Lexan roof.

The airgun range is open every day from dawn till dusk and it is considered an "always hot"/open range (for members of WAC).
Targets have also changed over the years, though we do like our "heritage" targets; some of them extremely challenging, like "Long Tom" who at 30 something yards may not seem too challenging, except when you get up close and personal and see that it is a 7/8" KZ up in the head of the turkey that stands relatively tall off the ground.

So, shoots at DIFTA are always a hoot, even when the MD decides to put too many 3/8" KZ's @ 15 yards, or sets up a 1/2" KZ at 42 yards.... LOL!

WAC has other shooting disciplines at which the members excel, WAC took a World Championship in a shotgun trap event recently, and the 3P airgun Junior shooters usually do very well in both classes (Sporter and Match).
So, it was logical to have some "loaner" rifles for the Junior shooters to try FT.
Mark Mayer worked very hard with the BOD's to get the project approved and once approved we started discussing the project.
The idea was to make TWO rifles that would be suitable for small framed shooters, like Jr's or ladies, or, in general, small framed persons.

Analyzing what was available in the market, we discarded the Crosman Challenger and the S200 on price grounds, we also discarded the Daisy 599 on weight grounds, and we discarded the Beeman chief on trigger quality grounds. Bigger guns were out of the question, so the Gauntlet, the Marauder, the Origin, and others of the size were simply written off from this RFI.
So, what was left was the DIANA Stormrider.
It was the least expensive one, and it was also the one that was best known / researched / documented; the one for which there was a reliable, high quality, regulator available (not the DIANA one), and where we could fairly easily swap the barrel for a Lothar Walther FT Match barrel.
There was ONE aspect where there was a "hole" in the project; and that was an externally adjustable power screw that was "elegant" and still allowed using the rifle as a rifle (as opposed to the "Army BB gun").
After all components had been ordered, & as they started to arrive, I was lucky enough that the FBI & DEA decided to commission their "Ballistic Gel blocks validation tools" , which allowed me the time and the resources to design and implement a proper power adjustment device that was completely internal to the rifle AND would allow a Free-Flight Hammer to increase the efficiency. Sorely needed when you want to shoot long matches with a 100 cc's air tube.

This is all you see. Inside there are 8 different parts that make the adjustment possible and still ensure that the hammer is in 'free-flight' when it hits the valve.

As with many things in life, we had to go over this project twice. My first tendency was to go to the WFTF power levels.
Why?
Because I assumed that the Jr's coming from the "Match" world and accustomed to 5.5 ft-lbs, would regard the 12 ft-lbs limit as more than enough.
BUT
Mark pointed out, that starting with 12 ft-lbs was a bit challenging as far as ranging and wind drift were concerned. So the first design that had served VERY well for the "BB guns" had to be adapted for the AAFTA limit (20 ft-lbs). Now, given the objective of an "entry level" FT gun, the real limit was a medium weight pellet at around 800 and something fps, something in the region of 14 > 16ft-lbs

Furthermore, for FT use, we faced two important "challenges" :
On one hand was the need to use a bigger aiming device and the location of the selected scopes:

As you can see from the pictures above, the short receiver does not leave a lot of room where to locate the scope.
There are two basic "free positions" in FT.
Those that shoot "AFFTA-Hunter" and "Open", shoot from a "virtual steady-rest", where the bucket/seat and the bipod OR the Price Harness turns the shooter itself into a solid rest. This allows the shooters to keep a somewhat vertical torso position, and the head goes INTO the scope, needing a forward mounting position. While shooting from the seating position, most shooters go back and therefore can adjust for a more rearwards mounting scope position.
In the end, we decided on offset mounts, which had to be milled off to allow the Hawke scope to achieve a vertical position in the mounts.
The short eye relief, and the location of the erector spring housing are, for me, a definite cause to NOT use Hawke scopes in these projects.

The other aspect you may note is that the sidewheel interferes with the magazine entry that is located on the left side of the carbine.
The single shot tray is open on both sides, but it is a definite success of one's dexterity to be able to load the pellet from the right. AND in FT there is a time restriction, so, fumbling pellets is the last thing you want beginners to do.
Use of a conventional single shot shuttle would also suffer from the same inconvenience. Since the Stormrider's bolt rides low and in front on the right side, the magazine is designed to enter and exit from the left side. Same for the conventional single shot shuttle.
In here, our good friend at CARM came to the rescue and designed a lockable single shot shuttle that operates from the right, thereby making it possible to use the large sidewheels that allow being competitive in FT.

A pre-production drawing of the right hand opening single shot shuttle. The red tab turns to lock in the shuttle in place. Available at the CARM website in 0.177" and 0.22"

In reality, after all the modifications, the only thing that suffered was the SUPERB setting of the triggers that is possible at 12 ft-lbs. Because the relatively simple, single lever, mechanism of the Stormrider trigger cannot keep the sear-breaking pull force equal when the spring that drives the hammer is exerting more force (needed for a stronger hammer strike, needed for a higher power output, which is expressed as a higher MV)..
Apart from that, the repeatability/uniformity was very good and what happens when you feed a consistent and uniform energy to a quality barrel, using a pellet that the barrel likes, is always the same: VERY good accuracy.

The end product does not differ externally too much from a standard Stormrider, the only noticeable modifications are the Lothar Walther match barrel with the HPM (High Performance Muzzle-weight) unit to tune the harmonics.

We also tried this method of scope mounting, but it was thermally unstable and we decided against it.

It is still, a very light gun and what would be possible, if needed, using a wooden stock, would be to shorten the LOP to 12" or less and add spacers to make it "grow" with the shooter.
What cannot be seen are all the changes INSIDE the gun:
Altaros vented regulator installed inside the air tube
Custom, tuned, self-valving transfer port
Adjustable FFH unit.

So, how accurate can these little guns be?

The little circles are 10 mm's across, and these are 10 shot groups at 25 meters (27 yards). Clearly, this rifle (remember there are two identical) likes the H&N BFT 9.56/4.50 at 856 +/- 2 fps
The gun yields between 35 and 40 shots per fill, so as long as the user re-fills halfway through the match, even a 72 shot match is perfectly doable.
Since the guns have TWO manometers (one for the reg and another for the tank) it is the user's responsibility to refill even if he has lost track of shots taken.
One important aspect is that these guns are DESIGNED to be filled to 230 BAR's and the regulator was BUILT for that top pressure.
While it is always interesting what the gunsmith can do, it is even more interesting what the person who commissioned the guns can do:

The message received was:
"Group of 5 at 55 yards.
I think these rifles are amazing for an entry level gun".
Ask any gunsmith and he/she will tell you that these are the comments that make the job worthwhile, warm your heart and put a big smile on your face.

Since the finish of the project, we have had one "clinic" where we tried to "recruit" shooters for the FT discipline.
The comments by all three shooters that attended was that the guns were amazingly accurate out to 55 yards.
Two of them were punching 7/8" KZ's at 35 yards (from the bench) with astonishing regularity; now, consider that that is a 40 Troyer target!
No piece of cake.

The rifles are a little bit on the small side for adults, but they are definitely ideal for youngsters and small framed persons:

In their finished form, the guns weigh less than 7# "all in".
And, at a fraction of what a dedicated FT rifle costs, we hope this will encourage the participation of some younger shooters.

I need to thank Mark Mayer for his patience with this project, the BoD's at WAC/DIFTA for their support, and renewed thanks to the FBI/BRF for their support in developing the FFH/Adj MV unit.

Thanks for reading, keep well and shoot straight!

HM

4 Comments

Africa called... and we answered!

9/9/2023

6 Comments

Pre-Event

Under the motto: "Afrika Ibiza / Africa is Calling!" The South African Field Target AA convened the FT shooters of the World to go to the foot of the Witwatersberg mountain range and compete for the awards and the places.
It has to be said that this was a triumph of perseverance and solid effort.
We need to remember that at the closing of the 2019 WFTC's in England, the South African Delegation made the required presentation / invitation under the same motto.
As life would have it, CoViD struck and the whole world had to make a "stop". As time passed and things happened, we all wondered what would happen, and then the FIDASC (Italy) volunteered to host the 2022 WFTC's. Which allowed the SAFTAA to re-gather forces and re-launch the idea.

At the end of the 2022 WFTC's we all viewed the invitation with some trepidation. Economics were not fully recovered, travelling was still a mess of sorts (lots of different regulations as to tests, masks, and vaccines), and South Africa just felt so far away....
In this specific vein, we have to thank Lauren Parsons, that, being a native-born South African made great efforts to convince everyone that the trip was doable and would de be enjoyable.

Greatest thanks need to go to the South African organization; they persevered, and they put together a great shoot! THANKS SAFTAA!

Now to the trip:
Having grown up reading the tales of Jim Corbett, J.A. Hunter, J.H. (Pondoro) Taylor, and others, it was ingrained in me that travels to Africa required packing light:

Yeah, that's IT! 25# in the rolling duffle and 23# in the short case (gun, tools and ammo included)

Flight has always thrilled me. Seeing things from above and looking at the clouds never gets old. I guess that, although I have grown old, I have never grown up, LOL!

The Team started coalescing months before the trip. A good thing about creating "WhatsApp" groups for specific persons and interests.
Some decided to take an extended holiday and take part of the family
Some others couldn't take the time off and we decided to be the "second wave".
We coordinated flights out of Atlanta, the stay at an "AirBnB" place, and the rental of two cars for the 5 of us (The Fantastic Five, LOL!).

Why two cars? Cameron thought that there would be far more bags than people (which was true in the end, LOL!)
So, Cameron took one car with David Alsup and Lonnie Smith and, with Leo Gonzales, I took another car .

Very impressed with the technology in Mitsubishi cars.

We had taken the precaution to book a hotel for the arrival night; not only that we didn't want to drive at night; more than driving after almost 24 hours of continuous travelling was not deemed smart.
For dinner we headed out to the only place nearby that was open called "On 21 Bistro", and had our first encounter with Biltong and local Karaoke... but that is another story ;-)

So we stayed the night near the airport and next morning we headed out to "Commando Nek"
It seems that in Afrikaans, "Nek" plays the same role as the French "Col", which would translate to the American "Pass". Meaning a route that is a bit lower than the mountains surrounding it.

Near the pass, there was a dam and around that dam, villages and "resorts" sprouted.
Our lodging was located in a fenced/gated community that bore the name "Mount Kos Estate"
At first, we were shocked by the mountain-goat "road" that led up, and up, and up; to the house, but the view was worth it.

180 degree view from our terrace.

Place was very good, with ample room for everyone and everything.

You can see Cameron's determination: "Yes, we were going to cook our own breakfasts!"

And we even managed to exercise a bit of our rusty pool skills (EMPHASIS on RUSTY) LOL!

Africa is an AMAZING place.
Not only is it the "Cradle of Humanity" (ALL currently living humans descend from an African Female that lived about 200,000 years ago, for a scientific explanation, read this).
It is a magical place where wildlife is a spectacle unto itself.
Of course we needed to "live a little" of Africa!
How else can you justify flying 16:30 hrs. just to get to another continent (and that excludes the continental travel within the USA) and not do anything else but shoot airguns?
;-)
No, we wanted to do a bit of sightseeing.
Of course, there are no grand buildings, cathedrals, historical places, art museums, or any of the more traditional sightseeing things we usually experience when the WFTC's are held in a European venue, but Africa is Africa! You need to take it all in as it is. And so, we drove a couple of hours to Pilanesberg National Park and what a place!
We got to see some amazing animals, in a pretty "natural" setting (it is not completely wild because wildlife in Africa is under severe pressure from illegal hunting, mostly driven by Chinese affluence and their desire for traditional "medicines" and "remedies" that incorporate wild animal's organs, or parts). So the place is fenced and guarded. Still it is a HUGE place (I believe something like 50,000 acres).
If I have my way, we're returning in about 5 years time, when the kids are more up to some real adventure and we're camping there!
Just a taste:

The "Second Wave"; from left: Leo Gonzales, Hector Medina, David Alsup, our guide, Cameron Kerndt, Lonnie Smith

Handsome Fellow

Auntie, Big Momma and Little Guy

De-horned to reduce temptations

Giraffe from Namibia (note the colour).

Local Giraffe (Colour)

No telefoto on this picture, yes, they were that close!

The extended family going away

Supersized goats

Meet the real Pumba

Small male Sprengbok

Smallish Croc (the pond was small)

Donkey in Pajamas

The littlest guys

We waited at a watering hole to see if we could see a leopard. And after a while, we heard one, it was awe inspiring to hear the grunts and the growls so close. Getting closer and then going away, then getting closer but at an angle.
Finally, like a fleeting shadow, a large female passed by; with a pace that seemed slow, she covered 100 meters in less than 5 seconds, only to disappear behind some thorn bushes, so, no picture, sorry, but it WAS the highlight of our trip to Pilanesberg.

On the way back we stopped at a local chicken joint, and I have to say that nowhere in South Africa did we get bad food. At every single place, whether humble or gourmet, it was good.

The 2023 WFTC's experience

USUALLY (meaning for most competitors), going to a World's is a question of a year of preparation AT LEAST.
Alas, when you are a gunsmith, you do not have that luxury.
I started the preparation well in advance, but then about mid-way, I got entangled in something I should not have and ended up spending valuable preparation time on a gun that, after delivery, was returned.
Against all policies, and all normal practices, I just returned the money so as to not deal with the very disagreeable person at the other end of the phone.
¿Could I have hung up and simply ignored him? Well . . . that's not who I am.

But let's get back to the story.

A "jinxed" rifle

I started more than a year ago preparing an alternate gun.
¿WHAAAAT?

LOL!, yes, an alternate. I had been toying with different materials and architectures for sliding compression chamber (SCC) airguns: TX200, HW97, HW55, D430, D460/K98, D48, D54, and maybe others that escape my mind now.
In these cases, there is no TENSION on the piston's body, only slight compression, and the function of the piston's body is just to carry the linear bearing that keeps the whole assembly aligned to the compression chamber's axis. Yes I know that some favour skirt-less pistons, but let's face it, alignment between two points that are an inch or so apart and two points that are full 4" apart is much better in the latter case than in the former, good alignment causes less chatter, and less chatter creates less vibrations.

So, I built a piston for my LGU (bought second hand from a GTA member that shipped it with a pellet in the chamber, LOL!), and had proven to be a very stable platform. If the technology was able to mature, then the lessons learned could be applied to all other SCC guns.

The piston gave good results, after as much shooting as other projects allowed, I started going to competitions with it and found that the gun was accurate and stable. Not so much the scope (more on that later), but it was manageable, as long as weather was constant (Ha! Opium dreams, LOL!)
The piston underwent a full 10 tins of BFT pellets (about 4k shots), plus all the other shots for warming and preparations for each session, so in all, I would say about 5k shots. And I was confident until the last competition before the worlds (Palmyra), where the MV started wandering all over the place.
Still, because I had this very complicated gun in the queue, I decided to ignore the signals, preferring to think that the spring was finally taking a sag. And so I embarked on the trip.

I always disassemble my rifle for air travel. Too much at stake in the "hands" of the blind and dumb conveyor belts that move most of the baggage through airports. Let alone the people that man the upward band elevator that puts all the bags into the belly of the plane (if the bag doesn't miss the entrance and then falls from 12ft down to concrete).
Upon arrival to Johannesburg, the guns had to be inspected.
We were asked for our "certificate"; apparently something you buy at the SA embassy/consulate, or your Safari operators buy for you to specify which gun (brand, model and serial number) is entering the country.
When we said we didn't need them, the guy went ballistic and insisted; we coolly, and collectedly, informed him they were airguns, but he insisted (it seemed his command of the English language was somewhat limited), he insisted, and we insisted. After about 4 tries, he went to look for a supervisor (a woman), and she came storming in about the need to have the certificates for the "firearms". So, we explained to her they were NOT firearms. That they were air-rifles and they were sub 0.22" caliber.
"Ah!, Oh!, yes, sorry! " and then to the "inspector" (in their own language, something that sounded like "yes, these crazy Americans are coming to Africa with BB guns!, Let them through!"
LOL!

What I had not noticed was that in the process of "verifying" the gun that was disassembled, they had taken out the stock and somehow managed to loose the part that linked the adjustable "wings" of the buttplate to the baseplate. And so, when the case was closed, a crucial part was missing already and nobody knew...
That was Jinx #1
When I tried to assemble my gun, . . . Lo and Behold! I had no way to connect and assemble the buttplate.
With my good friends, we took a dive into a hardware store as were returning from Pilanesberg, and found a way to get it working using a "T toggle anchor". Not as fully adjustable as it should be, but workable.

A few days later, we found out during the ALWAYS SO IMPORTANT first private shooting day, now a standard practice for the US FT Team. The gun started spitting pellets that could be seen in flight.
So, for the first time in my 12 years of going to the WFTC's I had to disassemble my gun and see what the heck was happening inside. That was #2

In here, the architecture of the LGU played an important role: Pre-load of the spring was barely 16 mm's, and disassembly was far easier than it would have been with a DIANA 54.

With the good help of my team-mates I was able to disassemble, semi-correct the problem and re-assemble the gun. I HOPED the correction was enough.

Hopes were shattered by the harsh reality of international competition. NO errors are pardoned, NO sins are forgiven. It is relentless, unforgiving, punishing of man and machine.

First day the gun was behaving properly at the sight-in range in cool weather but, when it warmed up, on the lanes, everything went haywire. Scope changed POA by more than 1¾ mRads and I was chasing my zero all over the place. That was #3

And, to add insult to injury, I discovered that the stock screws had come loose when we were 5 lanes from finishing the days shooting! That was #4

For the first time in my life, I posted a score under the 50%; WAY below the 50%, LOL!

BUT, as we learned in Italy "Never give up, never surrender".

As punishing as it is to skunk lane after lane, a true shooter never gives up.

The first day ended with a disastrous score.

As soon as it was practicable, we went to the nearest hardware store and bought some sandpaper, some cleaning fluid and some thread locker.
I took the gun apart, and reduced the size of the head to where it had "reasonable" tolerances, then assembled the gun using some Teflon lube that Cameron had and put the whole thing together again.
as painful as the process was, it was heartwarming to see and feel my teammates support.
Early in the morning, we adjourned to the sight-in range, and I proceeded with the whole setup process.
I was squadded again with Jacques Fouché, a young chap that had posted a more than respectable score on the first day.
As we started shooting things didn't look well till I could spot a few misses and then realized that the gun was settling in and that I should probably go back to the original range card. I did.
And as soon as that was done, things shaped up.
Now, don't get this wrong, in a WFTC's, ALL courses are hard, but some are harder than others. Particularly, blue targets in the vegetation's shadow are VERY hard to range (my day 1 course). And it is almost impossible to spot your misses after the first 3 or 4 lanes have been shot. My advice to MD's is that, IF they want to choose blue as a color (a permitted color under WFTF rules), please choose the lightest blue possible.
In any case, we were blessed with overcast skies and rather even temperature for the duration of the session, and, luckily, the results showed:

So, good comeback, but still another day to go.

For the third day, I was paired with a different squad mate, and we also experienced a rather pronounced change in ambient temperature, from the cool 70's we rose at, to the medium / upper 90's (very hot for a South African end of winter) , and that is what kept me looking (again) for a wandering zero.

I THOUGHT that I had pretty much got the temperature drift quantified, but the results show that the drift is not linear, but produces a sort of hysteresis curve, where the POA depends not only on the temperature, but also on whether the scope is heating up or cooling down. When you go from shadows to sun, clouds to wide open skies it is impossible to keep track, and so I spent most of the third day trying to find a zero, just to see it change as soon as I thought I had it.
Results were not AS BAD as the first day, but clearly the scope setup is not up to the tasks demanded in a world class FT shoot.

Which means that, as much as I like the scope, I am now looking for a different setup and/or replacement that is less sensitive to the temperature.

As a note: I have come up with a different way of setting up the mounts and, in principle, there is a huge improvement (that will be another story....).

In the medium run it may also mean that I need to start "clicking"; something I have resisted for many years as a waste of time and running the very real risk of "being one turn out".
I have a few scopes I want to test, and I will take it with a grain of salt, because clearly, this is something the scope manufacturers do NOT want to talk about.
So far, tests have shown that some scopes that do not change POA with temp, change the ranging. And some scopes that are of "lesser status" seem to be more consistent with the POA than scopes that are "high end optics".

For years I shot SIGHTRON scopes, but they lost the course and started offering things that are not as useful as others, perhaps with the new S6 they will re-consider and offer a truly useful reticle for FT. We'll see.

But enough of my woes, let's talk about the courses.

The collective memories of how the courses were setup

After coming back home, and as I re-started going to matches, I met two MD's that had a lot of questions about the courses.
So, I decided to recruit the help of my team-mates and achieved some sort of consensus about how the courses were laid out and why it was a TOUGH match (look at the scores of the top shooters and you will see that it was a hard shoot, compared to the scores of the same top shooters in previous years), here are some notes:

Comparative Difficulty between US courses and WFTC's:
The Springer Team feels that the performance was "up to par".
The fact that the Team members made the 1,2,3 AND, a somewhat bitter-sweet, team 1st, tells you that experienced shooters know what to expect at a World's.
USUALLY our PCP guys post much better scores, but in the case of the SA WFTC's, the course was laid out and was demanding of much more than simply good shooting.
a) There was a blue course that had most targets deep into the "veldt". The stark contrast between the very bright SA sun out in the open and targets in the shadows, made the blue course very difficult. In this sense, I can only think of TWO instances in the US courses where this happens.
b) There was a constantly variable wind. The courses were laid out between a basalt "Karst" and a dam/artificial lake. The thermals and the currents created by that peculiar arrangement were very tricky, constantly changing in direction and intensity.
c) Almost all lanes required a position change between first and second shot. This plays not only to the NSP / NPA, but also to the psychology of the shooter and the wind direction (and therefore real value).
d) Yes there was some walk involved, I would estimate about 2.5 miles to walk to the courses, then shoot them and then return to the central lodge.
e) Distances / Ranges were LONG. 80% of the targets were located in the 40-55 yards region and full 50% were between the 50 and 55 yards region. The positionals pushed the limit of the allowed ranges and, in fact, two had to be declared illegal for being too long. Among all the targets, only about one or two per course were 15 mm's reduced, and about five per course were in the 25 mm size, but placed at 32-38 yards.

Other factors that are at play in the WFTC's:
a) You are flying between 6 and 18 hours to get there. And there is a 6 to 16 hours time-zone difference that you need to absorb into your system.
b) You are also eating strange things and drinking, socially, at least.
c) The anticipation and the stress of an international competition is what it is, and there is no way to train for that, except by going to international competitions.
d) Shooting by numbers and having targets that cross lanes, unless you are used to it, it is very distracting.
e) The one shot per target could be easily emulated in the US with minor modifications to the match setup; for example: if MD's set up TWO shooting positions per lane, with variable distances between the two, the course could be shot ONCE from one position and then AGAIN from the other; that would allow the same number of shots with the same number of targets, but in two "rounds".
f) The non-manicured shooting positions is a factor, especially for the positionals.

Lastly, and I cannot stress this enough:
An informal poll shows that, worldwide, most successful FT Clubs DO KEEP a course open and available at all times that the ranges are open.
SOME clubs in the US are already doing this, and, we need to spread the word.
SOME shooters are privileged enough to be able to have their own course at home, but let's face it, not everyone can.
Shooting FT is the ONLY way of truly training for FT.

Let's try to depict the shoot itself in pictures:

Registration

Equipment Check (on the right in orange is the Head Marshall)

A daily visitor

WFTC's?

WTF's!

I am sure you can see the strings. Now, can you see the targets? Hint: They are blue!!!

Typical gate: Mat in fabric is staked to the ground, and there is a number at the "mat". Then there is a number at the lane marker, strings are color coded.

An "Afrika" target in blue

A giraffe, facing directly at YOU, in blue

Day 2 sight-in

M. Jacques Fouche, an excellent young shooter from SA

An "Afrika" target in white

Can you shoot an elephant with an airgun? YES! If it is small and metal and falls with a clank!

Typical lane; there is no "near and far"; there is far and farther.

Close up of the targets

Thread the needle!

Day 3 shooters' meeting

Now, meet YOUR shooters:

Alan Otsuka

David Alsup

Garrett Kwakkestein

Paul Cray

Peter Brooks

Lonnie Smith

Lauren Parsons

Cameron Kerndt

Leo Gonzales

Ken Hughes

Hector Medina

There were some shootoff's among the PCP shooters, and they were very exciting. Though the WFTF's procedure is not as fun:
For the shootoff, a two target "lane" is set. And the score that counts is the "lane score". Which means that if someone hits the near target and misses the long target, the match is undecided if the other shooter hits the far target, but misses the near one.
Personally, I prefer the "sudden death" version, creates more suspense, but that is a purely personal thing.
After the shootoffs, we all adjourned to celebrate or lick our wounds, according to the case.

A (ONE!) cold beer at the end of the day is always a good idea.

I'm not going to bore you with all the medals, trophies and presentations. Suffice to say that:

Garrett did a fantastic job at inviting everyone to the Rio Salado Shooting Range for the 2024 WFTC's

USA got the 1,2,3 in Springers

Lauren Parsons got the "High Lady" honours

David Alsup placed 1st in the Veteran PCP's

PCP team placed 3rd

The Springer Team USA had the honour of singing the "Star Spangled Banner"

Cameron Kerndt won the ONLY "Master Badge" in the Springer section

AND, he was the ONLY US shooter to win a "Master" badge.

The "Two Best Old Men with Springers" LOL!

When all was said and done, it was time to prepare the return trip, and when I tried to disassemble the gun for the trip back, I discovered that one of the stock screws was now frozen and the nut was spinning freely in a place no one could get into.
So, that was Jinx #5

Another trip to the hardware store to procure a drill and serially larger drill bits to get the head of the screw out.

Again, with the help of my friends, I could "de-capitate" the screw and the gun could fit into the case.

What used to be an allen screw.

Since then I have corrected the situation and I am using the best set of screws that the gun can be given

Walther should have thought of this from the beginning

Flat washers are glued to the stock, then the Nord-locs will keep the gun together with relatively little tightening torque. Funny thing is that it needs a lot more torque to take it apart than what is used to assemble, showing that the screws will never come loose on their own.

It was a good trip. Challenging, yes, in more ways than one. I am happy to have made it and happy with the results. Some may say: "there was little competition with so few shooters" but they would be missing that no one prevented the World from showing up.
And, as the saying goes: "showing up is half of the winning".
I still have a lot to learn, shooting the LGU is quite different from shooting the D54.
I'll see what comes next, in any case, that is the beauty of airgunning, it is a constant challenge, but you are not alone.

Keep well and shoot straight!

HM

6 Comments

First the Army, now the two TOP LEO's of the Nation

8/5/2023

3 Comments

Some time ago, I had the privilege and the pleasure to work with the US Army DevCom to make a tool to validate the ballistic gel blocks they use for tests:

https://www.ctcustomairguns.com/hectors-airgun-blog/a-bb-gun-for-the-us-army-c

It was a TRIP! LOL!

After a few months I was contacted by the DevCom person that had been my "liaison" for the project with a peculiar question: "Can we give your data to some colleagues of ours in other institutions?"
My answer was "SURE"

And I forgot about it.....

Suddenly the phone rings from an unexpected number in Alabama. Well, I normally do not answer the phone, so the screening system kicked in, and, for a change it was a serious call.
I picked up the phone and the voice at the other end says:
"Hello we're with the FBI"

¡GULP! ¿what did I do?

And then he continues: the guys at Picatinny Arsenal told us you made a small rifle that shoots BB's at the speed we need to test ballistic gel blocks.

Phewwwww!!!!! my soul returned to my body, LOL!

The conversation was VERY amiable and cordial and we agreed to meet.

We had a wonderful lunch and it was then that I was told that the Redstone Arsenal (that houses the Ballistic Research Facility - BRF) for the FBI and the DEA (two of the Top LEO's in the USA) needed a similar device.
But that they wanted it "improved". ¿How? no idea, just make it better!

And with this "open commission" off I went to work.

The project took a bit longer than usual for me (and that is, indeed long, as many of you know, nothing leaves the workshop without performing to its best, and that takes time).
The First improvement was relatively easy: the BFR had the need to test DOZENS of blocks in one "go", so a Magazine had to be developed that would work for BB's.
Luckily, CARM magazines came through with flying colors and made the magazine exactly as I wanted them.

Lothar Walther was out of smoothbore barrels, and so a special run had to be made. This time L-W made them without a choke, which proved to be a welcome idea.

BLS supplied the DIANA Stormriders.

ALTAROS air solutions made the small run of vented regulators for this project.

And the project started.

I will not repeat the process detailed in the Army rifle's entry above mentioned, so I will concentrate on the "improvement" of the FFH device.

At first I thought that what had been an EXTERNAL FFH control just needed to be installed inside the action, but the first tests proved me completely wrong. There was not enough space!.
And then I understood why most modern PCP's that have the characteristic (call it FFH, Sling-Shot, or any other name it is the same thing, use a LONG space to accomplish this.

I did not have the space, so, somehow the system had to be "folded".

After many weeks, prototypes, and tests, I went back to my spring-piston roots and designed a system that is structurally self contained.

Apologies that I cannot post a picture, as we are in the process of analyzing the patentability of the device. Suffice to say that it is a "drop-in" device that needs the change of two screws in the original Stormrider architecture and still allows a wide range of adjustability.

The results with this FFH device were quite good:

Remember that the International spec is 590 ± 25 fps, so were very clearly complying with the spec.

Additionally, my friends at the BRF requested the possibility to mount a laser pointer-sight, so a drooped Picatinny rail was added to the "tools", and tested at 5 meters (distance specced by the BRF), accuracy, for a smoothbore barrel shooting relatively fast for the projectile in question was not bad at all:

The little doughnut is 7 mm's across.

As I was getting ready to ship the three tools to Alabama, I sent a "Manual of arms" for their use and review and it was then that I was told that the "tools" had to be painted "safety blue" as they were non-guns. And so, I had to disassemble and paint the stocks:

If anyone says "SMURF" I'll personally kick him if we ever meet! LOL!
They are "cute" as my 6 year old daughter would say:

Looking back on the project, I do have to say that it was, again, a pleasure and a privilege to be able to serve these two institutions. They have a difficult job to do, and the BRF is, on top, also a "Go To" certified laboratory even for foreign entities.
Dealing with technically excellent people is always a pleasure.
Their patience and understanding of the process of innovation is commendable.

We are often told that without the US Defense budget's support of private enterprise we would not have many of the tech gadgets we so much enjoy (just consider the story of the transistor as an offshoot of the mixer diodes used in the early radar systems, and all that the little buggers detonated), but this is a first hand example.

Thanks and acknowledgements need to be presented to the components' developers and suppliers:
DIANA-BLS for the basic rifles
Altaros Air Solutions for the vented regulators
Lothar Walther for their excellent barrels
CARM for their very well made magazines
Daisy for superbly consistent BB's in their "Premium" line.
UTG for their Picatinny rails.

And, again, to the BRF for their patience and genuine interest in the micro-enterprise.

In the immediate future, we will report the application of the FFH device to the creation of specialized FT rifles for Jr. Shooters we hope to recruit from the Izaak Walton League's Wildlife Achievement Chapter, but that is another story.

Keep well and shoot straight!

HM

3 Comments

The North Carolina Classic 2023

5/31/2023

2 Comments

This year, the NCC was hosted by the Piedmont Handgunner's Association.

And it was a VERY NICE match.

Perhaps we should start by understanding what is "Piedmont".
Piedmont in most romance (derived from Latin) languages will mean the same thing: Foothills (Pied-Foot, Mont-Hill).
Why is this important? Because it gives us an understanding of what the "lay of the land" is.
In the USA case, the Piedmont goes from New York, to Central Alabama, and, clearly, North Carolina is well included.
Because the Piedmont is formed from the erosion of the Appalachians the lay of the land will be of smooth, undulating hills, with creeks and ravines, and sub-alpine vegetation.
The "Lay of the Land" also dictated which immigrants chose to make that region home. It is not surprising the foundational role of Scottish Highlanders, Germans, Moravians, Italians that created the populations centers and even gave the region its name (mirroring the Italian Piemonte, or the French Piedmont).
Usually, people like to settle in places that remind them of the "Old/Home Country".

For us, FT shooters, the lay of the land means specific challenges that need to be met, it means being aware, awake and alert to the changing conditions, and how the wind flows in "abrupt" terrain. How it shifts, shakes trembles, rattles and rolls, and how our "little pellets" are affected by it.

For spring-piston shooters, in particular, it also means that you need to be aware of the change in trajectory. Different elevations present different amounts of air mass per unit of volume, and so our MV sees some effect.

And, lastly, for low power shooters (sub-12 ft-lbs), it means that we need to be EXTRA CAREFUL to the "profile" of the winds along the trajectory of the pellet from muzzle to target.

Having laid down most of the premises, let's get to the trip and the shoot.

First of all I have to thank my family, for having taken the trek to this "new to us" venue. They had gone in the past to Ennice (6 hours drive), and to Pleasant Hill (4 hours drive), both NC destinations but this was the first time that we went to Lynnwood. Which ended up being an 8 hour drive due to construction and long weekend traffic. It was not easy on the kids, but they took it the best they could.

We arrived on Friday directly to the range just to make sure that the gun was reasonably in order and that we knew where the range was.
Proper road signs directed us well, and we found the range in no time flat.
There were no paper targets on the Friday session, but a plethora of spinners, bells and self-resetting targets were available and so I took the Walther LGU out of its case and started checking that everything was good to go.

I had shot the same rig at the local DIFTA match and the Palmyra match of a few weeks before, and I was still fine tuning some things. For this outing, the lesson from Palmyra had been that a buttplate that helped in making the shouldering repeatable was important, and the results at DIFTA confirmed the fact.
So I mounted a WKP buttplate and it proved to be exactly what I needed.

I had already mounted a WKP buttplate in my DIANA 54, but I had not taken into account the different cocking mechanisms and that brought problems. More on that later.

After some shots to settle in and then some more to confirm that everything was in order, I was pleasantly surprised to see that it was, zero was within 2 clicks and trajectory had not changed, so we adjourned to the hotel to do the check-in and settle down till the next morning.

Next morning, we arrived in time for the sight-in and, again, gun proved to be stable, which is quite interesting in a spring gun.
Zero and trajectory confirmed, family went off to the North Carolina Museum of Transportation (son is a fan of railroads), and I settled into the Chrono certification and the Shooter's Meeting.

All due formalities covered, we went to the lanes. I was shooting with my good friend Gerald Long. And he started cleaning lane after lane after lane. I didn't start too well, but I was not worried.
The course reminded me a LOT of the WFTC's in Portugal. Two of the courses were set up at the top of a small hill and the winds were a headache. They switched and swirled coming from all directions and the course was laid out in such a way that you had to move from one shot to the next. Not only rotate, move.

Apologies for my pictures, as they were taken with a waterproof camera that is "basic" to say the least.

To add, the position of most targets was about 18 degrees UP, and so it was VERY tiring (even more without a Hamster or a special FT Stock). Not enough to warrant a POA correction for elevation, but extremely demanding of those shooters that shoot unaided/unsupported.
By the time we reached the "cul-de-Sac" of the course (lane 20), I had let go a lot of points. Another lesson.

We were about halfway through the course when the standing lane came up and I forgot to keep track of where I was putting the force in the gun during the cocking stroke, and the upper "wing" of my buttplate snapped.
I was mad at myself and I never thought it would have such an important effect.

I still got three of the standers, and thought that everything would be OK.

Nothing further from the truth, after more inexplicable POI's, I decided to put a correction to the scope of -0.4 mRads, and I stopped posting big fat zeros. Still the proper correction would have to wait till the end of the match.
My partner Gerald was also having a hard time. He began the match by cleaning lane after lane, but suddenly he posted a zero. We thought he had been one revolution off, but upon further shooting, it was not the case.
He decided to not shoot the rest of the competition, and he was kind enough to stay with me as my scorer.
Day ended with a dismal 24/60.
But there was still another day and, even if it was forecast with nastier weather, I hoped that I would be able to redeem myself.

After turning in our score cards, we adjourned to the sight in range, and we confirmed that Gerald's scope had taken a dive into unknown territories.

First day of the Match went well, except for a couple of cold lines called to fix some targets; after that, everything went smoothly and we finished shooting at about 13:30 hrs. AND the weather held for us, as it started raining by the time we were having lunch.
We even had a chance to smoke our yearly (yes, only once a year at every NCC) stogie during the raffle:

(which, for a change, was good to me, LOL!) we agreed to convene at the Outback for dinner, and went home.

The forecast for the second day of the competition was that it would stat raining from 08:00 hrs.
So, after breakfast with the family, we arrived at the range and I started checking everything.
Wind was blowing somewhat violently, but some lulls could be used and there was no rain.
Targets were raised, some of them weighted and we proceeded.

I found that zero was still out, after -0.5 mRads of correction, finally I was on again.
Almost a full (-0.4 -0.5 = -0.9 )mRad! and just on account of a change in shoulder positioning.
I have always advocated the curved rifle pads for the DIANA 54, but this experience tells me that recoiling spring guns are even more unforgiving of small changes in shoulder positioning. Big lesson.
Several groups were shot at 55, 40, and 25 yards. The one I could not shoot was the 10 yards because the target had been blown down. And I thought it would not make too much of a difference. Again, a big mistake.
Chronoed the gun and there was only 1 fps between the day before (733.9 fps) and this day's reading (735.2 fps), so that was good.

After the shooter's meeting and the squadding, we proceeded to the lanes and the second match began.

I was squadded with Aimee DeLaCruz, as we shot lane after lane, Aimee was having problems. But as a good trooper, she stuck to the issues, corrected a few things and started connecting.

Photo by Russell Sauer, used by permission

Again, apologies for the bad pictures.
BUT, Aimee's father (Russell Sauer) was also taking pictures! And his pictures are very good indeed. You can see some of them HERE.

As the shoot progressed I was doing much better, till we reached the short 3/8"s targets. The first miss at 10 yards told me that something was dramatically wrong on the short ranges, and so more "zero hunting" took place over the next lanes.
When I felt I had some serious data, after lane 4, I took out my Tablet and re-calculated the whole trajectory. There was ½ mRad of correction that was needed in the short ranges (9 to 15 yards), from there on, I started connecting with the 3/8"s KZ's of the Yellow course.

One target in particular was an interesting lesson: It was at the top of the ridge and the wind was blowing over from the rear/left, so even though the wind was blowing left to right, most misses were a bit wide on the left and low. It was not a far away target and most shooters were shooting at 18-20 ft-lbs ME, so that was strange.
What was happening was that the wind was curling and started rolling over the ridge, creating a high pressure zone on the UPPER/RIGHT of the target which tended to shift the pellets to the left and down.

;-)

As I said, interesting course with much to learn from.

Overall, the end result for the second day was a much better 42/60 and the total for the 2 days a 66. Not bad for the third outing with a gun and pellet combo.

Only the last two lanes were shot under rain, so the weather was not as nasty as it had been forecast.

Could it have been better? Sure! ALWAYS! I don't think we can ever be completely happy; it's our nature. To polish, to perfect, to strive to improve. If we weren't like this, we would be probably be playing something else, LOL!
Perhaps we are somewhat masochistic in cherishing the opportunity to shoot in the rain, wind, and darkness but I have to say I had a ton of fun!

Photo by Russell Sauer, used by permission.

I am still looking into this QSC thing. Next step will be to implement the technology in a DIANA.

Question still lingers: What will I take to the WFTC's?

Keep well and shoot straight!

HM

2 Comments

The 0.20" cal. DIANA 54 Project

3/13/2023

4 Comments

In the way of an Introduction

Because Steve is well known to our readers, having spent considerable time creating "The Sled" and then tuning a DIANA 56TH, I will not introduce him again.

Those interested in his previous appearance here need to look into the following links:

https://www.ctcustomairguns.com/hectors-airgun-blog/the-saga-of-a-56-th

https://www.ctcustomairguns.com/hectors-airgun-blog/the-saga-of-a-56-th4603110

https://www.ctcustomairguns.com/hectors-airgun-blog/the-saga-of-a-56-th8042880

https://www.ctcustomairguns.com/hectors-airgun-blog/the-saga-of-a-56-th2541108

So, without further ado,

¡Enjoy!

HM

Guest Blog by Steve Herr

This project began in January of 2022 with email correspondence between Hector Medina and myself. I
was seeking advice on caliber choice for optimum accuracy at longer ranges in the D54/56 platform. My
current rifles at that time were two Diana 56's, both in .177, and I was questioning the performance of the
.22 caliber. Hector mentioned the .20 caliber as an option, and the possibility of testing one of his D54
CCA .20's. After a few more emails back and forth, I agreed to take on this project. Within a couple
weeks a package from Hector was received containing a D54 CCA .20 (minus the stock), along with a
Titan XS #4 spring, an O-ring Light piston and a couple tins of the JSB 13.73gr Exact .20 pellets. Also
included was a Harmonic Muzzle Tuner. Everything was packaged nicely in a foam lined hard case.

This was a new, old stock rifle that Hector had set aside in storage. It was complete with the Lothar
Walther .20 caliber barrel and OEM powerplant just as it had arrived from the factory. The outside of the
action was finished in matte black like the D56’s, and was marked 14 von 30. Since I started off with the
action only, the D54 CCA action was installed in one of my D56 thumbhole stocks to kick things off.
Hector's instructions for this project were quite simple
• Complete the 300-shot barrel break-in as per his guidelines
• Make it what I want after that
That was simple enough and gave me a blank slate to work with. I had read about the D54 CCA .20's in
the past, but never expected to have one in my hands to test, so this was an exciting adventure. With both
OEM and O-ring light pistons, along with the OEM and Titan XS #4 springs available for testing, I was
ready to go!
The outline for testing looked like this;
• Barrel break-in
• Velocity and Consistency
• Accuracy and POI Repeatability
Before moving on, let me explain the difference between accuracy and POI Repeatability. In my opinion,
you can have a very accurate rifle that is able to print nice tight groups, or hit a spinner target on every
shot. But, that does not necessarily mean it will have a repeatable POI. As the rifle is set up at slightly
different angles from shot to shot, things can change. Things like shot cycle, recoil and hold sensitivity
come into play, all of which can make a rifle less tolerable to changes in position when aiming at various
targets. Another critical component is rifle fit, which will be covered later in this article.
During the POI Repeatability portion of testing, I aim at various spots around the target, from top to
bottom and side to side, with a single shot at each spot. The target is then evaluated for shifts in POI from
one spot to another. I have seen minor changes in preload, and even TP size have an effect on this in my
sub-12 fpe rifles. On the D54/56, the sled tension comes into play as well. If you are too tight (or too
loose) on your sled tension, POI repeatability could suffer.
Ok, lets move on to the first part of this project...the barrel break-in.

Barrel Break In

The project began with a 300-shot barrel break-in as per Hector’s guidelines. This was a tedious process,
which involved shooting 3-5 pellets, and then pulling several patches through the bore using a Crown
Saver (see below). You then repeat this process for a total of 300 shots.

During the barrel break-in, velocities began to drop. There was a fair amount of spring buzz too, so I was
anxious to move on so that I could machine a delrin guide to fit this spring.
After the 300-shots were complete, the final step in the break-in was to fire lap the barrel with 5 shots
using pellets coated in JB non-embedding bore paste. Velocities dropped even more during this exercise,
and I could smell something burning. It turned out that the original breech seal had eroded severely.

The rifle was pulled apart and the original (black) breech seal was replaced with a Maccari OEM style
seal.
While the rifle was apart, I polished the ends of the main spring and machined a fitted delrin guide to
eliminate the spring buzz. A quick test at 13-yards showed a reasonably uniform group and a much better
feel on the shot.

Before moving on to the next phase of testing, I decided to make a dedicated press for this rifle.
Knowing that there would be numerous combinations tested, I wanted to make something that would not
stress the rifle in any way when pressing. While I have an Air Venturi Rail Lock compressor, I did not
want to use that for the amount of times this rifle would need to be compressed.
My press was based on a couple different designs that I had seen on the internet, with a few changes. The
action is supported in a rubber lined cradle to minimize chances for scuffing, and the barrel is not stressed
in any way when pressed. The barrel slides through a delrin collar, and all of the pressure goes against the
end of the receiver, which presses against the delrin plug that was machined for an exact fit into the
opening in the end of the receiver.

Velocity/Consistency testing

This was an eye opening experience for me, with many ups and downs. My goal was to achieve the
highest possible velocity, while at the same time maintaining target accuracy and repeatable POI.
Going into this project, the targeted velocity was 870-875 fps range. This idea was eventually abandoned
after seeing the rifle was gradually settling in at lower velocities, and any attempts to retain the higher
velocities were unsuccessful.
For the most part, the highest velocities were achieved when there was a certain degree of detonation
taking place, and this occurred mostly when using the original compression tube. As a side note, I
discovered that the original compression tube had a low spot, which was allowing the piston seal to skip
over it during the piston stroke. This resulted in unstable velocities.

After this defect was discovered, a brand new Compression Tube was installed and the detonation with
extreme spreads in velocity went away.
I was still seeking velocities of 870-875fps. With about 4 different tests already complete, I continued on
through approximately 14 additional tests of various combinations before accepting the fact that the
spring was settling, and 875 fps was not going to happen. It now looked like the max velocity might be
around 815-820fps. Time to accept that and move on.
Throughout the velocity testing, a number of mechanical variables were evaluated in different
combinations;

Original OEM
Compression Tube
Piston
Main Seal at 28.35mm
Main Spring

New OEM
Compression Tube
Piston
Main Seal at 28.58mm
Main Spring

Other
O-ring Light Piston
D460 Blue Breech Seal
Maccari OEM style Breech Seal
Maccari Main Seal at 28.42mm
70% Moly Lube
Krytox GPL205
Ultimox 226

Transfer Port Inserts
Brass
Alu-Bronze
416 Stainless Steel
Various sizes ranging from 4mm down to 3.65mm

Discoveries during the Velocity/Consistency testing

Original Compression Tube - The Original compression tube had a low spot on the inner wall, and was
unstable when using smaller sized main seals. This cleared up after a larger main seal was installed,
which measured 28.58mm at the lip. Much smaller than that, and the issues returned.

Transfer Port Inserts – A number of Transfer Port sizes were tested using machined inserts that were
based on Hector's design. I found that using softer metals such as Brass or Alu-Bronze would ovalize
under the pressure. When this happened, velocity would gradually start dropping off. Hector
recommended using steel for the TP inserts, so I switched to 416 stainless and have had no problems ever
since.

An added bonus to this insert design is that the pellets are seated into the breech at exactly the same depth
shot after shot. This contributes to more consistent velocities.
This is a pellet after being inserted by hand

This shows the pellet after the breech was closed, and it had been seated by the Transfer Port Insert.
The pellets seat to this same depth shot after shot.

D460 Blue Breech Seals – My results indicated that the D460 blue seals would tend to bleed off some
pressure when installed onto the Transfer port insert with the wide side facing out. Even with the thin
base on my Transfer Port inserts, the wider portion of the D460 seal was riding right on the edge of the
opening in the Compression tube. The inconsistent velocity due to pressure bleeding off was most
apparent when adding more preload on the main spring, or using transfer port inserts that were sized
below 4mm ID. Reversing the seal and placing the wide side down against the base of the insert resolved
this issue.

D460 Blue Breech Seal

Wide side facing out

Reversed with wide side down – The better choice

In order to properly seat this seal into the compression tube, I made a simple tool using an Allen bolt.
The inside of the bolt head was machined so that it could press the seal into place without damaging the
metal TP insert. A few taps with a small ball-peen hammer and the seal was solidly in place.

Maccari OEM style breech seals – Although these work quite well, they are an extremely tight fit within
the compression tube. Changing them out is not an easy task. Additionally, they are made of a harder
material and must be drilled out in order to fit the TP inserts. In comparison, the D460 blue seals are a
softer material, require no drilling and are easily removed when changing port sizes.

Original OEM Spring – A couple things happened with the original spring. First, the spring settled and
velocities eventually dropped to around 815fps. Next, the spring developed a very noticeable twist. This
was due to the fact that there was no tophat installed from the factory. For anyone who has used a tool to
compress a main spring, you know that they will twist and buckle in all sorts of directions unless you use
a properly fitted guide and tophat. When compressed on the shot, you should have little to no space
between tophat and guide in order to keep the spring straight. Having too much space between them will
only allow the spring to twist itself out of alignment. I eventually machined a 2.7mm tophat for this
spring to help keep it straight.

OEM powerplant and Transfer Port sizes – After the spring finally settled, the OEM powerplant did
not appear to do well with transfer ports much less than 4mm ID.

Titan XS #4 Main Spring – This was tested with the OEM powerplant several times. Before the original
spring settled in, the Titan spring was usually showing lower velocities. However, after “both” of these
springs settled in, I would say they were relatively equal in power output.
The difference I saw was that, unlike the OEM spring, the Titan #4 seemed to prefer smaller Transfer Port
sizes. In the end I chose this spring. In my opinion it is more consistent and has a better feeling shot
cycle.

OEM piston vs O-ring Light – In my opinion the O-ring light piston is more consistent, and has a better
feel on the shot. Just smoother all the way around. This piston is about 43.5g lighter than the Diana
OEM pistons, and may provide a slightly quicker shot cycle.

The supplied O-ring Light piston was a touch longer than the OEM piston, which reduced the stroke and
resulted in lower velocities. In order to correct this, I machined 1mm off of the nose. The pistons now
match in overall length and strokes are identical.

The only time I saw instability with this piston was when the Transfer Port size was reduced below 4mm
ID without reversing the D460 breech seal. After reversing the seal, the problem was resolved.

Krytox GPL205 vs Ultimox 226 – When I first started testing the O-ring light piston, I thoroughly
cleaned the compression tube out with acetone. This lube worked great for about 200-300 shots, but then
began to gum up and velocities dropped and became unstable. After disassembling the rifle I could feel
that the piston movement was sticking and very sluggish. I reached out to Hector and he recommended
using a 3-step process to clean things out to make sure all remaining traces of moly were removed. As
per Hector’s recommendation, the following three products were used in this order;

1) Citrus Cleaner (I used a product called De-Solv-It)
2) Lacquer Thinner
3) Acetone

Products were used in the order listed above, thoroughly soaking and scrubbing during each step. I was
amazed at how much black moly was still coming out of thecomp tube. This process took about 45
minutes until the rags were coming out completely clean. Both piston and compression tube were cleaned
in this manner.
Hector also recommended switching to the Ultimox 226 lube, which I did. At the time of this writing, I
am well over 500 shots into it and have had no further issues.
In the chart below, you will also see that at one point the new OEM piston was used. This was done after
I noticed that the piston rod was quite wobbly on the original piston. I don't think this was causing any
issues, but the new piston was purchased just in case. I never really noticed a difference between the two
other than the fact the new piston rod was nice and tight.
I could outline in detail each of the 26 individual tests that were conducted, but that would be a VERY
boring read for a lot of folks. Instead, I decided to post a chart below showing the specifics of each test in
the order of which they were conducted. On the right hand side of this chart you will see comments
indicating the success or failure of each test. You can also see that I began to overlap the accuracy and
POI testing. I would routinely test for accuracy and POI on calm days as a sense check of how the rifle
was doing on target. Velocity means nothing if you don’t have accuracy so it is important to watch both.
As you will see, the velocity eventually settled to around 812-815fps, at which point all of my attention
moved to Accuracy and POI repeatability.

Accuracy and POI Testing

With the velocity testing complete, my attention was moved to the target accuracy portion of this test.
Listed below are some key items that contributed to the final results on target, some more than others.

Scope at Mechanical Center - With the velocity testing complete, the barrel was tweaked for POI. I like
to run my scopes as close as possible to mechanical zero with POI set at around 30 yards. Prior to
tweaking the barrel, even with the compensated ZR mount, the POI was still a few inches low and left at
30 yards with the scope at mechanical zero. Mechanical zero allows the internal springs to balance out,
and can result in more consistent accuracy and long term durability of the scope.

Establish Rear Sled Tension Setting – This step was actually completed much earlier in this project. In
the early stages of tuning a D54/56, I like to pull the rear sled mechanism apart and polish things up. The
main thing that I polish are the base of the adjustment screw, and both ends of the coil spring. I feel that
this allows for smoother adjustments and movement of the ball. I also like to polish the surface on the
base of the sled rail bracket that the ball rolls against.

After the polishing is complete, all oil, dirt and old Loctite, etc, are cleaned from the threads before
reassembling.

Next, I establish the best tension setting for the rear sled, or at least get it in the ballpark. As a starting
point, I generally begin somewhere around minus 1 turn from max. With sled in the unlocked position,
turn the adjustment screw in (clockwise) until it bottoms out. You then turn counterclockwise 1 full turn
to begin your testing. From there, make tiny moves in either direction (maybe 1/8th turn at a time) while
observing performance on target. When making changes, always take a few shots after an adjustment was
made before monitoring performance on target. Sometimes the disruption of removing the rear stock
screw in order to make an adjustment will cause a few erratic shots until things settle back in. This really
applies anytime you pull things apart to make changes.

Documentation is key here, so take notes as you go. When you find what you believe is the best setting,
you will then need to verify this setting.

In order to verify your setting, make sure that the sled is in the “unlocked” position. Counting the turns
as you go, turn the sled tension adjustment screw clockwise until it is maxed out. You then turn it
counterclockwise this same amount. You have now returned to your original setting. Document this
setting.

After the setting has been documented, loctite the adjustment screw using blue, medium strength. The
process I follow is outlined below;

1) Add a drop of blue medium strength Loctite above the screw as shown below

2) Insert your allen wrench and back the screw out counter-clockwise 2 turns, and then turn it back in
that same amount. The threads will now be coated with Loctite and it will be set to your desired
setting

3) Immediately dab out the excess Loctite from above the adjustment screw and you are done.

The process above will insure that no Loctite migrates down into the spring/ball mechanism. If any
Loctite gets to the spring and ball, the ability of the sled to unlock and travel smoothly will be greatly
diminished, and accuracy will suffer. So, you must be very careful in not allowing this to happen.

For the majority of this project I was battling with fliers on target, even after setting the rear sled tension.
The rifle would perform well and show some nice tight groups, but would then have a couple random
fliers, some of which were fairly substantial. I began to move away from 5-shot groups in favor of 10-shot
groups as I was working to resolve the issue with fliers.

Even on my 13-yard indoor range, the effects of the fliers could be seen.

Harmonic Tuner - I am a big supporter of Harmonic Tuners and went through several tests to verify
optimum settings during this project. Even with the unstable groups and fliers, I could still see which
settings resulted in the tightest core groups on target, while ignoring the fliers.
Multiple tests revealed that 4 and 8 o-rings continually came to the surface as the best settings. The fine
tuning of the HT allows you to closely time the exit of the pellet from the barrel to an end point in travel
of the muzzle on the shot. It does not take much to make a change on target.

Let’s shift all focus onto the things that were contributing to the fliers.

It was quite evident that the rifle wanted to shoot. I had many tight core groups, but the random fliers
were ruining things. There were a number of things contributing to the fliers, which I will outline below;

Harmonic Tuner coming loose – Even the slightest movement of this tuner will change POI and allow
the barrel shroud to slide back and forth resulting in accuracy issues. The HT must be pressed snug
against the o-rings and barrel shroud before snugging up the set screws. The supplied screws kept coming
loose, and I did not want to loctite them.

Here you can see the effects of a loose HT on target at 28 yards

The supplied set screws were replaced with nylon locking screws from McMaster Carr, which took care
of this issue.

Barrel Shroud (Inner Sleeve) moving – The thin inner sleeve that surrounds the barrel started sliding
backwards within the outer shroud. This happened several times and it did not want to stay in place.
Accuracy was immediately impacted as soon as it began to shift. Hector recommended that I flare the
back end of the inner sleeve to keep it from sliding underneath the outer shroud. After doing this, the
sleeve hasn't budged. I marked it so that I can always see it at a glance that it is staying in place.
In the attached pictures you can see how far it would shift.

After flaring the end of this sleeve it has not moved

Tight spot in breech – Pressing pellets through the bore revealed a tight spot in the area where the barrel
is pressed into the outer breech cylinder at the factory. I would like to mention that many spring piston air
rifles have this issue to one degree or another, so this is not just an issue with the Diana.
As I slowly pressed a pellet through the breech, it would get tight at this one spot, and then free fall with
no resistance until it hit the choke. Because lead is soft and does not spring back, the tight spot essentially
resizes the pellet, allowing it to lose contact after the tight spot until it hits the choke area. This is not
good and can definitely contribute to fliers as pellets are unstable through much of their travel down the
bore until they hit the choke.

At first I attempted to polish this out using felt pellets on a brass jag, but that did nothing. I then decided
to hand lap the tight spot using form fitting lead slugs screwed onto a brass jag. This was a tedious
process where I used a number of lead slugs and compounds of 120/220 grit, 400 grit and then a final
polishing. The slugs were an exact fit to the rifling and once removed could not be reinserted. After
pulling them from the breech, and new slug had to be made.

A generous coating of grease was applied as a carrier for the compounds, while I worked solely on the
tight spot, testing pellet fit often. When I was satisfied that the tight spot was leveled out, I worked the
entire length of the breech to blend things in, followed by an overall polishing up to the choke with felt
pellet on a jag using JB followed by a mild polish. After this was complete, pellets pressed through the
bore had a nice even pressure from breech to choke with absolutely no free fall.
In the photo below you can see the difference in the rifling engagement on the pellet. Pellets were
pressed up into the barrel, but stopped before they reached the choke, and then pressed back out through
the breech. The pellet on the left was “before” the hand lapping, and the pellet on the right was “after”.
Big difference.

Front Sled – The front sled was a little rough and had inconsistent tension when moving. It also had a
slightly loose fit to the rail.
For most of this testing I had worked solely on the rear sled tension, and although the rear sled tension is
absolutely critical in maximizing accuracy on the D54/56 platforms, it did not get rid of the fliers.
After studying the design of the front sled and its single rail, I decided to modify it in a way that would
tighten things up and remove the looseness, while at the same time allowing tension adjustment similar to
the rear sled, but with smoother movement than the OEM ball bearings.
A summary of what was done:

• Existing springs/balls were drilled out and removed.
• Balls were replaced with pads machined from phosphor bronze, using the original springs (minus
1 coil) for tension. Nylon locking set screws were added so that spring tension on the feet could
be adjusted.
• Two holes were drilled on either side of the sled block, and PTFE gibs were added to hold tension
against the rail using nylon locking set screws.This eliminated the slop between the sled block
and rail.

This idea was borrowed from Hector's accurized ZR mounts.

After both front and rear sled settings were established, screws heads were marked and scribe marks
added to the top of the sled blocks to enable a quick check that settings were holding

While on the subject of the front sled, it is worth mentioning that sled tension is a critical component in
accuracy on this platform. I initially thought that running the front sled with the least amount of
tension/resistance would give the best accuracy, and when the spring loaded bronze feet were first
installed I had extremely low tension on the front sled. Accuracy was much worse.

The front sled must have tension on it for maximum accuracy and repeatable POI. It kind of acts like a damper for the rear sled, smoothing out the unlocking during the shot, and adding consistency to the
overall sled movement. It is a balancing act and with the added adjustments on the front sled, fine tuning
can now take place for optimized accuracy. Set it too loose and accuracy will suffer. Set it too tight and

you will begin to feel some recoil and the rifle will become more hold sensitive. I found it best to tighten
up until I felt a little recoil and then back off a little bit. Same goes for both front and rear sleds, if you
begin to feel some recoil, you went too tight.

The two things that had the most impact on getting rid of the fliers were the breech lapping and
the front sled modification, with the front sled modification having the most impact overall.

Results on target were clear, fliers were gone. Here is a 10-shot group at 25 yards

In addition to the fliers, I was also experiencing random shifts in POI whenever I attempted to run the
metal self-leveling washers in place of the OEM metal and rubber washer assemblies inside the stock.
With self-leveling washers in place, the rifle would shoot well, and then all of a sudden the POI would
shift. I would then adjust my scope and be fine for a while, but the POI would then shift again and I
would have to adjust once more. The problem was eventually discovered as outlined below.

Self-Leveling Washers – When the self-leveling washers were first installed, I polished the mating
surfaces to allow them to level out more smoothly when the stock was in place. I also added bronze
bushings for a tighter fit onto the post of each sled. While the bronze bushings were a nice modification,
the polished surfaces were not. I discovered that they were too smooth and would allow the washers to
shift when shooting, resulting in shifting POI.

Polished

Hector installs them unpolished, so I decided to purchase another set from McMaster Carr and test them
unpolished. I still added the bronze bushings, but did not polish them. I tightened the stock mounting
screws up to 30 inch pounds and have had no problems since. They stay put and offer what I believe to
be a more consistent and rigid sled movement without having the variability of the OEM rubber washers.

Unpolished

With the fliers now under control and no more POI shifting, there were some
additional changes made to enhance accuracy and improve repeatability of POI

I eventually received the OEM D54 stock from Hector and installed it for the remainder of this testing
.
Recoil Pad – After switching over to the Original D54 stock, the length of pull was too short for me, and the cheek rest was way too low. This caused neck pain and issues on target.

The first step taken was to install a Morgan Premium Curved adjustable recoil pad. This has an aluminum
base that requires custom fitment to your rifle, and you must pick a size that is closest to the dimensions
of your butt stock. I ended up letting the OEM plastic spacers in place for some added length, which
worked out perfectly.

Cheek Rest – The cheek rest was way too low and I was unable to align myself properly to the scope
without lifting my head off of the stock. I reached out to Hector for suggestions, and ended up purchasing
one of his leather, padded cheek rests. I had used one of these before on a previous project, and
remembered that they were quite comfortable.

With the leather cheek piece installed, it was still too low. The ZR mount has the scope sitting a little
high, which creates a need for additional height on the cheek rest. After some research I decided to make
a custom fit cheek riser out of EVA Foam. The EVA foam is easily formed and shaped, and could be built
up to the perfect height, while fitting nicely under the leather cheek piece. A total of 25mm of additional
height was added in order to position me properly behind the scope.
In order to hold this EVA foam riser in place beneath the leather cheek piece, a thin piece of silicone
rubber was added between the wooden stock and the EVA foam riser. This held things in place nicely as
if it were glued.
In the pictures below you can see the difference before and after. The time spent making small
adjustments to the recoil pad position and cheek rest height was well worth it. This process reminded me
of my years spent shooting target bows. The fit of my bow was so critical in being able to repeat my
shots on target.
Fine tuning the rifle fit greatly improved the ability to repeat POI around the target. Being able to
position yourself consistently shot after shot is extremely important for both accuracy and POI
repeatability.

Before

After

HT Tuning – Tuning the HT is another critical part of getting the most out of the rifle. As mentioned
above, I had already been through a couple sessions of tuning the HT. However, now that the fliers were
under control, the OEM stock installed and the rifle fine-tuned for fit, I wanted to run one final test to
verify the ideal setting.
The results were now more clearly defined, and when I reached 8 o-rings it was quite clear that this was
the winner. This was the 3rd test where 8 o-rings had made the list. This test was test conducted at 37
yards. You can see the pattern changes as the muzzle swing transitions from vertical to horizontal, and
then settles close to an end point at 8 o-rings.

The target was then moved to 50 yards and I was pleased to see 7 shots under 1⁄2” ctc

Knowing how much even the tiniest change of the HT effected target performance, I wanted to take this a
step further. The o-rings are about 1.4mm thick when installed on the barrel, so each additional o-ring
moves the HT that amount. I wanted to fine tune in smaller increments in either direction of the current
setting of 8 o-rings. In order to accomplish this, I made up some delrin spacers of various thickness.
From that point on, my settings were identified in millimeters rather than # of o-rings. My starting point
was 8 o-rings, which was 11.2mm's. After some time on target I found that going over 11.2mm's hurt
accuracy. However, going slightly less than this improved it. Final spacing ended up at 10.88mm's,
which falls somewhere between 7 and 8 o-rings.

Sled rails – The sled rails can shift a tiny amount from front to back during the shot. Although it is only a
small amount, it can alter sled tension when sled first starts to move on the shot. In my opinion, having
the sled movement as consistent and rigid as possible is best for optimum accuracy. Shims were added
under the e-clips to take up this slop.

Trigger Work – The T06 was completely disassembled, cleaned, sear surfaces polished, then re-lubed. I
also removed 1.5 coils from the trigger tension spring. The OEM trigger adjustment screws were
replaced with TX200 adjustment screws for improved adjustability. I also added a set screw for adjusting
the length of stage one. Press nuts were installed after reassembly to keep the cross pins in place.
Trigger is now set for just under 10oz. I have had it as low as 8oz, but bumped it back up a little.

I also installed a shim under the plastic spacer at the front of the trigger assembly. This allows for a
slightly better fit within the receiver

Transfer Port Insert Sizes – During this project, a selection of transfer ports of various sizes were
machined for testing. While the OEM powerplant preferred a larger port, the O-ring light piston along
with the Titan XS #4 spring performed best with smaller ports. The 3.75mm port performed well, but the
3.65mm port seemed to have the edge with more consistent velocities straight off the rack cold and no
apparent loss in velocity over the 3.75mm port.

Pellet Lube – A series of tests were conducted indoors at 13-yards comparing lubed pellets vs unlubed.
Testing consisted of the following;

• T-9 (Spray) Lubed
• Unlubed
• Pledge Polish (Baked)

In the end, the Pledge baked pellets won for consistency, accuracy and POI repeatability.
Note: The Pledge baked testing was the only test that started out with a cold bore, and you can see that the
first shot was a touch to the left.
Shots are numbered on the target and coincide with the chronograph numbers

Preparing for another batch of Pledge Polish baked pellets

The next day I moved outdoors for a quick test at 37 yards to verify things at distance. This target was
shot first thing in the morning, cold off the rack. I wanted to include the cold bore shot so that you could
see that there is a slight difference in POI on first shot cold off the rack. This mirrors what I saw the
previous day on the cold bore shot (circled on the target above)
Cold bore shot slightly left, then 5 shots under 1⁄4”.

Other Modifications

Stock – After receiving the OEM D54 stock from Hector, I wiped it down with denatured alcohol and
sealed it inside and out with 3 coats of Maccari's Royal London Oil.

Cocking linkage pin – After breaking several OEM cocking linkage pins at the back of the threaded
adjustment rod, I replaced it with a hardened steel pin from McMaster Carr as per Hector's
recommendation.

Stock Mounting Screws – The Phillips head screws were replaced with button head allen screws,
machined to fit into the recess of the OEM washers.

Cocking Handle – A rubber stopper was added on the inside of the cocking handle to keep it from
smacking against the pull rod hinge at front of compression tube. This also helps to add a little more
space between the threaded cocking linkage rod and the sled reset bracket. You do not want the threaded
rod to contact this bracket as it will negatively impact sled movement and your results on target. You will
also feel the rifle begin to kick if this rod starts to make contact with that bracket.

Cocking linkage threaded rod adjustment block (rear) – This block had a sloppy fit to the linkage
pins, which may have been contributing to the broken pins. After several broken pins, I removed this
block, drilled out the hole and machined phosphor bronze bushings. The bushings were installed with
loctite 638 and have an exact fit to the linkage pins. I had no broken OEM pins after this, but opted to
replace them with hardened steel pins anyways per Hector's recommendation.

Rifle Info
Piston – O-ring Light
Lube – Ultimox 226
Main Spring – Titan XS #4 with fitted delrin guide, 1.8mm tophat and 3.2mm spacer
Breech Seal – D460 Blue reversed with wide side down
Transfer Port Insert – 416 Stainless Steel at 3.65mm ID
Trigger Pull – 9.9oz
Rear Sled Setting – Minus 9/16 turn from max
Harmonic Tuner Setting measured from end of shroud – 10.88mm
Stock Screws – 30 inch pounds using the spherical washers from McMaster Carr (Not the OEM rubber)
JSB 13.73gr at 20.21fpe

This has been another enjoyable project and in the end, I liked the rifle so much that I ended up
purchasing it from Hector. At 20+ fpe it is extremely accurate with a repeatable POI. With the addition
of the adjustable recoil pad and custom cheek riser, it fits me like a glove. As mentioned at the beginning
of this write-up, until now I had only read about the D54 CCA .20's. I feel honored to now have one in
my collection.

Hector, I cannot thank you enough for offering up this rifle for my testing and eventual purchase. Your
trust in me is much appreciated and it was a pleasure to work with you from start to finish on this project.

Closing Comments by the Editor

As a long-ago Teacher/Professor, I know how thrilling it can be to have a good pupil.
The slow and deliberate process of changing one thing at a time is well reflected in Steve's process and work.
His way of leaving no stone unturned, even in the face of difficulties and extensive waits, starts, stops and fits speak volumes about Steve's character.

It was truly a privilege and a pleasure to accompany Steve along this long path of research, enlightenment, discovery, and innovation.

In the old days Apprentices needed to present to the Master a piece that demonstrated that they had learned the skills needed for a trade. And then, fully-fledged tradesmen needed to present a piece to the Heads of the Guild to achieve "Master" status.
This is the origin of the word "masterpiece".
And this is what Steve has presented today to the airgunning community.

I hope it has been enjoyable to read, and I hope Steve's work will motivate others to do a systematic, scientific, exploration of different parts and sections of the "lowly piston airgun". A machine so complicated that we are still in the process of beginning to understand in all its complexities.

Thank you, Master Steve, for your hard work, your dedication, and your unswerving focus.

I hope we can continue to cooperate in the future.

Keep well and shoot straight!

HM

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Hector Medina

2012 US National WFTF Spring Piston Champion
2012 WFTF Spring Piston Grand Prix Winner
2013 World's WFTF Spring Piston 7th place
2014 Texas State WFTF Piston Champion
2014 World's WFTF Spring Piston 5th place.
2015 Maine State Champion WFTF Piston
2015 Massachusetts State Champion WFTF Piston
2015 New York State Champion WFTF Piston
2015 US National WFTF Piston 2nd Place
2016 Canadian WFTF Piston Champion
2016 Pyramyd Air Cup WFTF Piston 1st Place
2017 US Nationals Open Piston 3rd Place
2018 WFTC's Member of Team USA Champion Springers
2018 WFTC's 4th place Veteran Springer
2020 Puerto Rico GP Piston First Place
2020 NC State Championships 1st Place Piston
2022 Maryland State Champion WFTF
2022 WFTC's Italy Member of TEAM USA 2nd place Springers
2022 WFTC's Italy
2nd Place Veteran Springers
2023 WFTC's South Africa Member TEAM USA 1st place Springers
2023 WFTC's South Africa
2nd Place Veteran Springers