Hector's Airgun Blog

The Rifle that COULD have saved Walther's springers

9/28/2024

Disclaimer.-
The conversion done here was carried out by a professional gunsmith. No warranties implied, or otherwise, are intended in this article.
Do NOT attempt this conversion if you are not completely qualified to do so.
This conversion has NOT been sanctioned by Carl Walther or UMAREX
This conversion proved safe IN THE GUN that it was performed. We cannot guarantee that all other guns will receive the conversion in the same way.
Please do not ask for measurements or dimensions, Connecticut Custom Airguns cannot provide these data.
All designs and parts' shapes and dimensions are proprietary to CCA and Carl Walther brand as applicable.

Background:
In the course of history, it often happens that when an entity; be it a corporation, a person, or a country, is close to the end, the entity performs their best.
When talking about spring-piston airguns, a friend has accurately commented that they are either "breaking in" or "breaking down".
Some years ago (1993), the company Carl Walther GmBH was acquired by UMAREX., the condition however was that the "Olympic and Target Style" rifles would be kept in a separate division that would be independent and that the firearms division would not get into the airguns.
So, under the guidance of the "new management" at UMAREX, the sporting section of the company began the development of a new line of spring-piston airguns.
We have already commented on the LGV and the LGU in a number of our entries, so we will not go there. We are, also, not interested in the lower line of rifles that UMAREX brought to the market to compete on price (Terrus, Parrus, etc.).

What "piqued" our interest some years ago was the very "Last Hurrah!" of the German company.
A somewhat "simplified" version of the LGV, and the last of a line that started back in the 1960's.

And I am talking here of the Walther "Century Varmint"

A very rare rifle that, AFAIK, was not even offered for sale in the USA in any appreciable numbers.

I had to purchase it from Krale in the Netherlands:

Of course with shipping and banking charges, it came in at a bit more, but still, this price was something that realistically COULD have been paid by a good many precision interested shooters.

So, after some waiting, and a lot of tinkering, I ended up with this beastie:

From the outside it pretty much resembles the LGV, similar outside contours; and the tell-tale unlocking lever in the breech-block (where the "V" comes from since the 60's) .
The stock also resembles the Varmint stock that was sold as an accessory for the LGU.
Now, mechanically speaking there are strong differences between the LG "family" and the Century Varmint.
I have taken the liberty to use an Exploded parts Diagram from the Bagnall and Kirkwood website, they offer some spare parts, so the link is always useful:

B&K were sent an EMail with a respectful request to use this diagram in this article. Good time was allowed for them to answer. Without an objection, it is used here in the spirit of "Fair use" and with full respect of their copyright.

The first thing you may notice is that this piston does NOT have a stem.
So, naturally, the trigger's sear is a sort of "ramp" that goes up and locks the piston at the skirt's edge. When the sear breaks, the ramp is pushed forwards by the piston's skirt and then it can fall down, freeing the piston that is pushed by the mainspring, to fly forward, completing the spring decompression fase of the cycle and compressing the air in the compression chamber.
In opposition to the LGV, this gun does NOT have an inserted "Sleeve" to form a compression chamber of smaller bore. This piston, the seal and the compression chamber are all 28 mm's, while the piston, ID of the compression chamber and seal of the LGV are 25 mm's

"Cognoscenti" among us will immediately say "that is no good!" And they would be right from the POV of shooters that are extremely happy with guns that deliver truly smooth power at 10-12 ft-lbs. and weigh (in practical FT garb, between 15 and 20 lbs.

BUT, this gun was not designed for those shooters.
This gun was designed to put out between 12 and 14 ft-lbs with good accuracy and medium weight at a low / median cost.
In reality it achieved all of these goals. It weighed less than the LGV because it did not use a sleeve. It delivered more "stable" power because the swept volume of a 28 mm piston can do better than a 25 mm's piston with the same pressure. And it cost substantially less than the LGV because the piston was simpler, the trigger housing smaller, the parts less complicated, and the rest of the parts were less sophisticated.

Those "Cognoscenti" shooters received with a cold shoulder the LGV and then the LGU, and some of them are now lamenting not having purchased one (of each) .

Inevitably, the conclusion for "Firma Walther" was that the market was not ready for high quality springers.

At any cost.

And, in a way, they were right, only recently have high quality spring-piston airguns achieved that price bracket, first the DIANA 54 and now the AA TX-200 US.

So, after a VERY short run (something in the LOW hundreds), the WHOLE of the Walther Spring-Piston rifles was removed from the roster.

So, WHY did this rifle failed to save the line?

The trigger.

I had always wondered why German airguns from the year 2K forwards, seemed to be designed by people that have NO IDEA of what shooting is all about.
Until I went to Germany.

With the "remodelling" of the whole country (as the "Berlin Wall" fell), a multitude of elder workers at all levels were displaced by younger persons with degrees and PC - CAD capabilities which seemed to be able to solve everything from the design phase. The solutions proposed made sense from the materials, production, and engineering sides. "Wunderbar!" ¿no?

Well, no. A lot of those solutions made no sense once analyzed from the shooters/tinkerers/gunsmiths POV's

And this is the perfect example. If you look at part 601.200.08.1 you see a "well designed trigger blade"
Except that it is made of plastic. Not only plastic, it is "structural" plastic, meaning it is not even solid.
AND, if a lot of shooters protested and cried their hearts out when DIANA came out with the T01 plastic trigger blade that is stout, rigid, and, more importantly for us gunsmiths: Customizable....
This trigger blade is a joke.

The rest of the gun is a masterpiece. The barrel of the one I have is good, accurate and stable. The Muzzle piece, being threaded and not having a particular orientation, can be used as a Harmonics Tuner. The lock at the breech block is taken directly from the LGV, so it is quality.
Guide, spring, tophat, piston, seal, everything mechanical is truly an engineering achievement.

But that trigger!.....

Even the stock, yes they are ALL synthetic (ALL Century Varmint stocks I've seen are Synthetic, not to be confused with the Century LGV that is a different gun altogether, that has both, wood and synthetic stocks); they fit well, are truly ambidextrous, and make shooting comfy.
I did not resist the temptation and improved the stock somewhat, but we'll come to that later.

Let's look at the Shakespearean "Fatal Flaw" of this rifle.

Theoretically an adjustable two stage trigger; when we open it we see this:

In the picture above, the two springs (one for the lower lever and the other for the trigger blade) have been removed for clarity.
Do note that the sear is the "ramp" we talked about and that it has an elongated hole that allows is to move aft and fore with the cocking cycle.
The steel bushing on top gives strength to the assembly, aligns the piston's skirt and works as a retention point for the skirt. Between the bushing and the ramp, the piston cannot go forwards without a trigger pull.
In usage, the trigger is only adjustable so much, and definitely not up to what is required for precision shooting.

We need to remember that hunting with an airgun is an exercise in precision because we cannot count on energy to do the job for us. Placement is everything.

Part of the fault lies in the adjustment screw, it is too short and abuts before the trigger can become really crisp., so we changed that screw:

A healthy coat of Vibra-Tite ensures that the adjustment does not "disadjusts" by itself.

And we need ANOTHER screw to actually make it sensitive, so we added a nut:

AND a screw:

Since the blade is very thin molded plastic, we used a manual drill to avoid mishaps.

Could we have made a metal trigger? Yes, at considerable cost in time. Time that I did not have.

Once that was done, we could tackle the pellet selection process.
We tested some pellets then made a worksheet and sorted by energy levels. It often happens that the best performing pellet is at the top or top 3 of the energy performances of any given spring gun.

In this particular case, the A-A Field Diabolo did give the best ME, but at the cost of a higher sSD (sample Standard Deviation - 18% higher-). AND it also happened that in testing at the target (at 25 m / 27 yards), some groups were VERY good, some VERY bad. I suspect that this particular tin was not the brightest candle in the chandelier. Perhaps other tins may behave better, but in THIS case, the H&N B-8 were the best, more on that later.
Once the pellet was chosen, the muzzle piece was "tuned" using calibrated washers. The rifle needed less than 0.2 of a mm to go from good to great results (you can barely see the separation/washer in the picture) and what is important is not the results here, but the fact that the muzzle piece CAN be tuned to other pellets or other pellet batches.

I mentioned that the stock had been "improved", so let's talk here about the stock and the interfase between stock and action.
In spring-piston airguns, one of the main enemies of consistency and accuracy is the mating of the action to the stock. The vibrations inherent to the operation of a spring as a powerplant, induce vibrational forces that can loosen the stock screws, so the screws were changed and star & Nord-Loc washers provided to all the stock wells that had previously received flat steel washers:

The other aspect that needed improvement was the buttpad.
The OEM buttpad is nice, but it is designed for VERY low mounts and VERY short necks, LOL!
So a Morgan adjustable buttpad base was inletted into the stock, taking advantage of the hollow rear portion:

Once mounted it allowed to be adjusted to the LOS of the scope and the long neck of this user:

The last obstacle we found was that the gun has "anti-droop".
Yes, and this is not the first one I find in the Walther lineup that has an upward slant in the barrel, to allow for "flat" mounts to be used without needing drooped mounts.
Well, we had prepared a ZR mount, but these have a 4 mRad droop compensation and there was no way to sight in a scope with that.
So I acquired a BKL adjustable mount.
It is a good piece of kit. BUT (always a "big but" gets in your way, LOL!), it would not go "low" enough, so some hand fitting was needed.
The rear adjustable ring was filed off to allow the roller/spacer to reach the bottom of the groove:

Like so:

Once that was achieved and the mount put together, it could finally be "flat":

OK, so the question that needs to be answered:
¿Was all this worth it?

I think so.

Even though I cannot keep the gun, I came to love the simplicity, lightness, and accuracy; it comes up naturally to a "quick ready" and is a wonderful shooter; AND, I have found a very good home for it.

This little beastie is one of two airguns that have been selected to start a long time PB'er and great shooter in his path to airguns enlightenment and illumination.

;-)

AND, this is the test target that will go with the gun; what is, in general terms, a typical group:

Some of you might say:
"that's not a good group, I can shoot like that all day with my "xxxx", LOL!
Perhaps you are a much better shooter than I am,
But this group, from 27.2 yards (25 m); from a handheld sitting position (FT); in shifting winds of around 14 mph coming from all sides (hurricane Helene on the way), is no "slouch".
The black aimpoints are a bit under ½", so let's put this into perspective

TEN shots covered by a dime.

Not bad, ¿huh?

If you ever come across a "Walther Century Varmint" that's up for sale at a reasonable price, grab it. They are good guns that can be outstanding performers with a little bit of TLC.

Keep well and shoot straight!

HM

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Night-Vision for Springers keeps advancing

6/12/2024

2 Comments

DISCLAIMERS:
1.- ALWAYS FOLLOW THE LAW! Shooting at night-time produces very different perceptions in different parts of the country and the world, so, make sure you are well aware of your laws and that you are not infringing on anyone else's right to safety, security, and tranquility.
2.- Application shown here is safe for the gun intended. NO warranties are made or implied.
3.- Shooting at night requires 10X more care plus the need to ABSOLUTELY identify your target and make sure of your backstop. Take your time, wait for the shot, and make sure to make it count.
4.- Also make sure you visit/scout the place during daytime and that you KNOW the spot like you know your "farcebook" welcome page, or the nicks and scratches in your favourite airgun stock.
5.- If you know the spot and you know the distances, and you know your target, practice under as similar as possible conditions. Do not wait for the hunt to actually practice your viewing, lighting of the "work area", keeping track of personal gadgets, simplifying of trajectory data and having the facility to consult it at all times, even in the dark.

Now that is over let's get down to it:

It seems that every 4 years

something interesting pops up.

8 years ago I published the first version of this with SIGHTMARK's Photon

4 years ago, it was the turn to post the newer version using the SIGHTMARK "Wraith"

Now, it is the turn of a relative newcomer : PARD

PARD has already some history in Europe, where night/dawn/dusk hunting is almost preferred. Less people around, less bother.
We in the US still are in somewhat of a legal "labyrinth" because it seems that almost every county can set different rules, and in some states, it comes down to township/parish.
So, the first disclaimer is there for real: ALWAYS FOLLOW YOUR LAW.

It was a friend/customer the one that first pointed me in PARD's direction. He was looking for something within a $200 budget and didn't really want a dedicated unit. He wanted an "add-on" to his scope.
So, we undertook the research and the analysis of the specs and settled on one unit that he tested extensively, sharing his results.
After that, it was a question of waiting till someone came up with the need.
And it happened a few weeks ago.

The carrots, lettuces, and tomatoes of a good friend were being raided by different rodents that surfaced at dusk and night. Some of them edible, some of them not, but they still did damage.
And so, the HIGH COMMAND (Wife), decided to send the troops (Husband) in.
Well, it was a good excuse to get a new gun and the night equipment to accomplish the mission.

;-)

The gun chosen was a DIANA 48, that he sourced 2nd hand independently, and when the sighting system question came up, it was an easy choice.

PARD has made the effort to keep to the "standard configuration" of the traditional rifle scope.

Which was one characteristic that made the demise of the "Photon" doubly lamented. The requirement of using different "housings" made the use of Picatinny bases mandatory. And that excluded the use of the ZR mount, thereby risking the vibrations and inverse recoil of the springer ruining the sight.

PARD kept the "morphology" of the traditional riflescope and therefore allowed us to mount the unit using a normal, 30 mm's, Accurized ZR Mount.

Here it is in a different 48:

And here is a detailed view:

It is a bit high, but that is easily corrected with a lace-on cheekpad.
The rear focus has a HUGE travel availability because this scope focuses from 6 yards to infinity, amd the thing adapts easily to external cameras, even though there is an INTERNAL camera that is MUCH MORE than a simple camera.

Now, how does it work?

Let me tell you BEFORE, what elements in the scope ARE NOT what they seem to be;

The elevation and windage turrets are NOT the elevation and windage turrets.
The elevation turret is actually a knob that works pretty much like old "iPod" devices and that then got into cars and almost everything else: the knob rotates to move around a menu, and pushing the knob changes the menu where you are operating, either getting you deeper into details, or long pushes save and exit what you have just adjusted.
The knob lets you sight in the scope to the gun in the same way that the Photon did (you bring the POA to the POI) there are 6 profiles you can save / store, it allows you to choose between 6 reticles, it changes colors and contrasts. And performs other functions.

The "windage and parallax" turrets, are in reality the battery housing. The battery goes clear across the unit. There is NO OPTICAL path between the front and rear halves of the scope.

What in other scopes are the controls of the illuminated reticle, in this scope are the buttons to operate the Laser rangefinder (Oh, yes, this model does have a laser rangefinder capable of determining distances from 6 to 1,200 yards, with a precision of ±1 yard); at this area you will also find the buttons to take pictures, or video. Though there is a setting where the recoil of the gun automatically pre-triggers a few seconds of video and stores from the "before" the recoil moment till after, in order to fully capture a shot.
The rear block also houses the slot for a memory card and external connectors.
The big, round, blue-ring'ed button is the on/off

So, how does it work?
There is a VERY sensitive photosensor in the front half, that photosensor transmits images to a round display (no TV / squarish displays here), that is what your eye sees at the rear half.
So, you are looking at a display that "augments the reality" of the image formed by the photosensor.

The onboard computing capabilities add info, like range, in/de-clination, direction (yes it has a compass), and other stuff.
The onboard computing power is powerful enough to have a ballistic calculator (G1) that actually PROPOSES you an aimpoint for the distance measured by the LRF, if you have it working and you have programmed the parameters of your projectile/system.
And YES!, it does accept BC's in the 0.0X region, so most quality pellets, even in the small bores, will be able to take advantage of this facility.

You should still hold off for the wind, we still have not reached the point where there is a wind-shear radar in the device to help you with that... but . . .¿Who knows in another 4 years? LOL!

The Images:

The images are clear and sharp, again, taking pictures of scope images is not easy, you need three hands and 4 eyes, so I did my best. Apologies for some fuzziness:

Here is what the LRF tells us of a target at measured 10 m:

And at 23 m:

The colored bands are more due to a slight difference in sampling frequency between camera and display, the colored bands do NOT exist in the image viewed.

Now at 37 meters:

And now at 50 meters:

The fact that the LRF can pinpoint the distances to a relatively small object is VERY interesting.

I didn't delve deeper because PARD has honored every single spec, and I may need to buy my own scope to really play with it. LOL!

The behaviour in total darkness: impeccable. Taking pictures: impossible.... Sorry!

At a one dollar under $800 it is not an inexpensive unit, and it is, nominally, at the same price as the Photon of 8 years ago was in its own time.
The FUNCTIONALITY of the device, however, is a LOT greater and if we take into account what inflation has advanced in these 8 years, it really is an interesting proposition.

Would I take it out in daytime? ABSOLUTELY! It gives the benefits of a device that can handle many different scenarios/situations and conditions.
Would I like to shoot FT with it? Certainly YES! It would still need to be handled carefully in the 10 to 17 yards range because +/- 1 yard within the "near Zero" is not good enough for pin-point hits at tiny KZ's.

There are quite a few videos of this model in YouTube, just search for the model, and the Manufacturer's page for this model is here.

If you are in need of a well executed night vision scope that looks like any other scope AND that works well in daytime, this is a worthwhile investment and it merits a really good look into it.

Keep well and shoot straight!

HM

2 Comments

Taking an HW50 through "Boot Camp" Part 2 ©

5/16/2024

0 Comments

When is a gun finished?

As a gunsmith I would have to declare that the project is finished when the scope of work agreed to with the customer has been achieved. OR, when the budget runs out.

I've handled projects under BOTH mechanisms and, they both have advantages and disadvantages.

There is always the feeling that "we can improve on this"

At the same time, my first "boss" in real life used to tell me (more often than I wished) "Done is better than perfect".

And so, there has to be a balance, and even more important than the balance is the fact that your customer / user needs to end up a "Happy Camper".

In my projects with Official entities, there is a clear spec. from Average MV, to sSd, to weight, range, autonomy, energy, etc. It's easier to deal with professionals because they can put their needs in numbers.

In THIS case, the "want/need" was a rifle capable of tackling the FT lanes with some confidence. As my friend put it: "A gun you would be happy taking to a serious Match".

:-\ Built on an HW50? .... that's a tall order! Still, we proceeded and tested many combinations to arrive at a stability and a quality of shot cycle that belied the light weight of the system and the smallness of the rifle.
You can read all the internal aspects here.

Now, as promised, we will look , briefly, into the accuracy potential of the "finished" system:

The barrel was sleeved in a very tight fitting CF sleeve, and the HPM (High Performance Muzzle weight) at the muzzle allows for tuning to the harmonics of the specific pellet in question.
The HPM will be "cerakoted" in a color to approximate the CF dark grey.
Because of the way the HPM works, there is a rather strong tension in the barrel when in use.
Scope is for tests only; a SIGHTRON SI 4-12 X 40 MOA-20 reticle SFP AO, and is mounted in an Accurized ZR mount 1" rings.

Testing at short range

Tests at 10 meters were absolutely boring.
Stacking pellet on pellet in a hole hardly larger than the pellet itself gave us no differentiation between the two most efficient pellets tested in the powerplant tests.

So, we waited for a good day, and proceeded to test at 25 meters.

Unbeknownst to me, the gun will be used in the AAFTA version of "Hunter" Division, Piston Class.
So this test was performed shooting off the knee in the FT shooting position.

Rather than shoot one group, I shot the US standard test taking the average of 5 X 5 shot groups (at least).

The gun performed well with the first batch of pellets at hand, lubed with T-9:

As is normal, some groups are better than others, and for an unknown gun with a small scope, with about HALF the weight of my normal FT rig (8# and change vs. a bit less than 15#), I think the little rifle did quite well.
The shooter,. . . not so much, ROFL!
In all groups there is ONE shot that spoils everything.... well up to a point. Reality is that even with that "little martian" floating around included (totally attributable to the shooter), the groups are not bad and they do represent that, properly sighted in, all of the shots would have gone into a reduced KZ (15 mm's) at 20 meters

Weather dictated that we stop the testing and for several days weather simply did not cooperate.

By the time we could tackle the tests again, several days had passed and we had not had the chance to pitch one "flavour" of pellets vs. the other.

Finally, we had the chance and this is the result:

There's a ton of info in this target, so I might as well explain what is going on.

First of all, these shots were taken from the seating position but with a crossed sticks bi-pod, because that is the way the gun will be used. Not my favourite position, and not one in which I have a ton of experience.
I do have to say that it seemed to me that the gun shot better when the bi-pod was placed forward, near the end of the forearm, close to the location of the front stock screw.
It is my firm belief that IN THE END, what matters is that the guns I make are "shootable" by the end user in the way he/she wants to use the gun. I cannot see any value in producing benchrest guns that are absolutely horrid to shoot in a more practical way.

Coming back to the target:
First two rows we tested different lubes, the top row tests the T-9 lube that is applied cold; the second row we tested Pledge that needs to be baked in.

There was 2 MOA's difference in POI between one and the other, putting into relevance how impactful can be a change of lube in the functioning of the rifle. BOTH lubes are non-dieseling, BTW. AND both lubes produced pretty much the same energy at the muzzle.

Wind was predominantly flowing from right to left, so we "zeroed" in to each distance using the first one or two bullseyes.
Rows 1 & 2 were shot at 25 meters
Row 3 was shot at 38 meters
Row 4 was shot at 50 meters
all from right to left.

When we started, the wind was ebbing and flowing at around 5 kph (3 mph), but towards the middle of row 3 all hell was breaking loose and gusts and switches were happening and caught me off of my guard many times.

Still, counting the bullseyes that were shot "purposefully and properly sighted in", we would have to take into account:
Bullseyes 3,4, and 5 of Row 2 with a score of 3/5; 3/5; and 4-5/5 (depending how you look at them)
All bullseyes in row 3, acknowledging that I was being moved by the wind, let alone the pellet in flight. Scores for that row would be: 4/5; 1/5; 1/5; 1/5; and 3/5
And then row 4, where I tried to wait till the proper conditions presented themselves, bur clearly failed to fully identify the conditions. With scores of: 2/5; 4/5; 3/5; 4/5; and 1/5 because I simply gave up and shot a group when conditions were what I had hoped for. It is reassuring that 4 pellets clustered in a tight group, meaning that I need to learn more about wind, LOL!

After the card was done, I went into my weather app and this is what it said:

When I started, wind was a leisurely 5 kph, by the time I was finished, it was 3 times that! LOL!

The crux of the matter is that the little gun proved more capable than expected. Delightful to shoot, and a pleasure to carry.
I should have gone into the woods for some squirrels, but there was no time.

I still cannot see the much vaunted "quality" difference between this HW and a normal, run of the mill, 34 EMS.
I do concede that the HW50/99 is the "basic" / "beginner" model in the HW lineup.

Hopefully, I will soon get a reasonably priced HW97 of RECENT manufacture and see for myself "what gives".

While the HPM is off being cerakoted I will take the time to look into the concentricity, homogeneity and uniformity of the compression chamber, if I find anything relevant, I may post a "Epilogue". Mostly to satisfy myself, as it is clear from the performance at the target, that the gun achieved the "ready for FT" status.

And so, as far as this project is concerned, the gun is "finished".

;-)

Keep well and shoot straight!

HM

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Taking an HW50 through "Boot Camp" Part 1 ©

2/13/2024

8 Comments

Part 1.- The Power Plant

Disclaimer.-
The conversion done here was carried out by a professional gunsmith. No warranties implied, or otherwise are intended in this article. The turning/milling operations carried are sensitive, not devoid of dangers and of a high precision nature.
Do NOT attempt this conversion if you are not completely qualified to do so.
This conversion has NOT been sanctioned by Weihrauch & Weihrauch GmbH & Co. KG.
This conversion proved safe IN THE GUN that it was performed. We cannot guarantee that all other guns will receive the conversion in the same way.
Please do not ask for measurements or dimensions, Connecticut Custom Airguns cannot provide these data.
All designs and parts' shapes and dimensions are proprietary to CCA and Weihrauch & Weihrauch GmbH & Co. KG and their Weihrauch brand as applicable.

Benchmark

When tackling an unknown rifle, I like to do a "Benchmark" test to see where we started and evaluate where we ended.
In THIS case, it was impossible, and the story is peculiar.

A friend asked me to make two sets of springs for his HW50 using Titan springs as basic material.
We consulted with the Titan manufacturer (John Knibbs & Co in the UK) and the suggestion was to use a Titan #7, so we ordered the springs and when they arrived, a couple of guides were made and shipped.

Time passed and then I was alerted to the fact that the springs would not allow the rifle's piston's stem to engage fully with the trigger, thereby the gun could not be cocked.

So I got the rifle and the springs with the instructions to add a CF sleeve to the barrel and to get the rifle up to WFTF level (that means sub-12 ft-lbs, and accurate to 55 yards).
And . . . the process began.

The first thing was to establish the real "capacity" spring-wise of the little rifle.

A search in the Internet came out with three important things:
1) most serious uses/best substantiated & published results of these guns are from the UK, under the 12 ft-lbs/0.22" cal. guise. Energies in the mid 10's and great 3 shot groups are reported in the E-press. Of special note are the "Sandwell Sports" special runs that seem to embody what would be an ideal "UK Garden rifle", though some of those specially commissioned guns are very capable at ranges in excess of 55 yards in the right hands.
2) the CURRENT HW50 in the US is the HW99 in the rest of the World.
3) the numbers for bore and stroke were all over the place, LOL!.

As a gunsmith, I have ways to measure the guns in all their states, and an important measurement is what's the REAL stroke of a specific rifle.
The way to measure this is to disassemble the gun, remove the spring, and use a "proofing" spring.
These springs are weak springs (2.5/3 mm's WD) that are powerful enough to make the gun operate, but would probably yield less than 3 ft-lbs if used to fire a pellet.
So a proofing spring was installed and the distance of travel between the positions of the piston's stem's notch start was measured:

Here we are marking the start and the end of the stem's notch.

Now the gun has been cocked

And we measure the distance. In this case the measurement was 71 mm's

To our "chagrin" the Titan #7 has a solid length of 99.06 mm's

Huh?!?!?!?!?!?!?!

So, a courteous Email was sent to HW.

And the very nice answer was:
"...
The cocking stroke of the mod. HW50 is about 71 mm.
...
"
Ooops!

We're in trouble. With 71 mm's of stroke there is no way a 26 mm's bore piston will reach the 12 ft-lbs without combustion in 0.177" cal.

After some conversations with the owner, he was gracious enough to allow experimenting to see where we could take the gun.

And from there, the title!

I assume everyone in the USA is familiar with the Army motto "Be all you can be"

Well, this little "recruit" was going to become "Private HW50" in boot camp, and we WERE going to find out what "All that he could be" meant.

Taming the beast

The "beast" here is HW's extremely complicated method of assembling the gun.

You not only have two main pins (as in almost all other brands); you have, in addition, 4 little "blocks" that have very peculiar shapes (luckily, all of them are identical), and are destined to reinforce/lock the "closure" of the trigger block into the mechanisms tube.

I KNEW I was going to assemble and disassemble this rifle MANY times, so I needed to device a way to do it efficiently, with the least amount of effort possible and SAFELY.
And so, I went looking for a "secret weapon" something that would allow me to push the little blocks out of their recesses without damaging anything.
After some time at the bench contemplating how to build a tool, I was tired and I returned to my desk, only to find the solution staring at me in the face:

Yup!
Those little thingies have two spring "legs" that, when removed, look like this:

AND, if you choose the right size, and if the little blocks are not damaged, they push BOTH blocks out at the same time, but we are getting ahead of ourselves.

Let's start at the beginning of the disassembly.

First of all, with a quality gun, ALWAYS look for the best fitting screw driver you have for EACH slot.
Especially because European slots are "thinner" than American slots AND are parallel; and so, sometimes you NEED to MAKE a special screwdriver for specific brands/models of guns.
IDEALLY, gunsmithing screwdrivers have hollow ground blades, meaning that the "blade" that enters the slot should have PARALLEL sides. Something that is not common in SAE screwdrivers.
Most modern airguns are adopting industrial socket standards, like Allen; even Torx are not unheard of.
BUT HW is a traditionalist, and so, slotted screws you will get and the best screwdriver needs to be found/made.
For THIS case it was not too difficult; on one hand the gun had been disassembled previously and it showed, the slots were a bit "chewed", but that gave us a chance to "chase" a bit the slots, so that they fit perfectly a SAE screwdriver:

For reference and informational purposes ONLY, this is Craftsman 9 41586 + WF / 5/16".

IF the gun had arrived to me in pristine condition, I would have ground the tip to make the sides parallel, but in this case it made more sense to use the screwdriver's tip to "iron out" all the burrs and ensure a positive grip and drive.

At the price of these drivers, it really makes no sense not to customize the driver to the screws of a new gun.

Once the stock screws are removed, the trigger guard can be removed:

IMHO, the inletting could be a bit tighter, as the shelf that supports the guard, while enough for any reasonable torque applied to the REAR trigger guard/trigger block screw, it does seem a little "slim".
It would be fairly easy to cut a square box for the trigger block, there are tools that do that; alternatively, a much smaller tool could be used to cut a "rounded corners square hole", but either would imply changes in the tooling / CNC process and undoubtedly would add cost to the gun.
Now, no one in his/her right mind would put 45 in-lbs of torque into that rear screw, but here comes another problem: That screw is about 2mm's too long. If you tighten it enough to prevent "play" (which would bring vibrations and inconsistencies), then the trigger mechanism will not latch.
It MAY be that different stocks require different lengths and therefore ALL the guns get the same screw, That's fine as a "value engineering" but if this is your model, just take a file and remove between 1 and 2 mm's of length and be done with it.

So, stock removed, you have access to the mechanisms:

This gun has no "cocking shoe", which means that extra care needs to be put on the fit of the spring to the ID of the piston, and the piston to the ID of the tube., but more on that later, let's keep on disassembling "Private HW50".
First thing is to push out the trigger block pins, yes, you need to do this first!

You start with the REAR PIN:

This allows you to hold the safety AND raise the rear end of the trigger block.
When you raise the rear end the safety will, literally, shoot out under spring pressure, but since you are holding it, you will not loose any pieces.
Now, you remove the FRONT pin:

POP Quiz!
If you only follow the pictures, you will get it wrong, hope you are reading carefully the text.

;-)

With the pins removed, you can lift the trigger guard by the REAR section and remove it from the gun.
At this point in time you still do not need a spring compressor.:

Once the trigger is removed, cock it:

It will make life so much easier upon assembly.

And now you can use our "secret weapon" to push the locking blocks out:

If some of the blocks resist this pressure, then aid yourself with your screwdriver:

Depending on how "rough" the locking blocks are, you may opt to sand them down a bit, or not, that is up to you.

It may be that, at first, some of the little blocks will not come out at all, even under screwdriver's aid.
In that case, as long as ONE of them comes out, you can use a slimmer drift punch to drive it out:

Now we are ready to head to the spring compressor, and before anyone says anything, if you don't want to use a spring compressor, be my guest.
Using a spring compressor is the SAFE (for both, the GUN and YOU) way.
If you do not want to be safe, or have little regard for YOUR gun, then "it's your party and you cry if you want to"; just reserve your opinions to yourself.
To do it easily and properly, you need to have some sort of "thrust bearing" between the rifle and the end of the spring compressor:

I have all sorts of bits and pieces, and so, this is just the stub of a Teflon bar. It will not mar the rifle's finish and it will allow the rear plug to rotate with little friction.
In this gun, the "thrust" of the spring against the piston is contained by that "locking lug" in the closing piece that gets rotated into place when assembling, and rotated out of "lock" to disassemble.
So a LITTLE pressure into this piece from the spring compressor (just to make sure there is no contact between the "face" of the locking lug and the mechanisms tube), and the pieces can be rotated "out of battery":

Once completely rotated "out of battery" then the closing piece can begin to slide out:

In here, it must be said that for some of the spring/guide combinations used here, which require a somewaht substantial pre-load, it was beneficial to rotate the TWO parts into each other, rifle AND closing piece.
For disassembly, this may also apply.
In any case, once the piece has begun to slide, it can then be slid out completely:

As long as you are only changing a spring, this is as far as you need to go.
At this point in time, you swap the old for the new spring, assemble in reverse order, and you're done!

However, if you want to change the piston seal, or the piston itself, you will need to further disassemble the rifle, and you start by disassembling the hinge pin in the forks, which requires to break the barrel to remove tension from the hinge/forks interfase:

Start by the "nut" on the right side of the gun, again, ensure that you select the best possible screwdriver for the job, if you do not have an ideal one, make it.
Once the "nut has been removed, you can remove the split washer underneath it :

A magnet is useful in these cases and once the split washer is removed, you can turn over the rifle, unscrew and take out the hinge-pin/screw from the left side:

Once the hinge-pin/screw has been removed, you can "wiggle out" the barrel block being careful not to loose the very thin washers that the factory put in there.

Once the barrel block and the forks have been "divorced" then the cocking lever can come out of its recess:

And once the cocking lever has come out, the piston can slide to the rear, while the barrel assembly can slide to the front:

With the piston out, serious measurements can take place and the planning for the modification starts taking shape:

If you ever get the piston out of your HW50, do look at the inside of the compression chamber. If it looks like this:

It needs a DEEP cleaning, LOL!

Plug the TP with a small wooden dowel, spray with "Gumout" Carb cleaner, cover the rear, stand vertically, and let it sit overnight. Then scrub with a long wooden dowel wrapped in paper/cloth and clean again.
Then clean with acetone or lacquer thinner (that also is made up of acetone), till you get something like this:

The "tune"

Using the metric punch pin as a "position holder" (3rd picture above) we can clearly see that the piston has ample room for improvement.
The Vortek seal at the top left (black one) is the same for the 95 as it is for the 50, which is peculiar, but that's what it is. The OEM seal is even taller. There's 0.4 mm's between the two, but that is what makes the rifle have (in HW's own words) "a stroke of about 71 mm's".

We also measured the TP and it is not too long.
One peculiarity is that, while not completely horizontal between compression chamber and barrel, the inclination of the transfer port is somewhat shallow:

Barely 20°, which means that the origin of the air flow from the compression chamber into the barrel's breech is at the top of the piston, not at the center.
And this may be the cause of an asymmetrical wear/galling of the piston, but we'll talk about that later.

We ran a rather long and exhaustive series of tests with "Private HW50"

We had FIVE springs, two guides, two top hats, and two sealing technologies (and three different ORing Materials).
We did NOT run all the possible 120 different tests, but we did run a fair number, enough to have a good "grasp" of what makes these little rifles "tick".

I MUST emphasize that NONE of these tests were run as "conventional" tests. ALL test were restricted to the "pop" gun (as per Cardew's definitions), with NO dieseling allowed to contribute to the energy output.

A true "Boot Camp" for the "recruit".

Just to list the springs we tested (later cut down to max allowable length for THIS piston/gun combination):
Maccari XLD 120-775/30
Vortek 118-780/30
Vortek 118-745/30
Vortek 113-780/30
Titan XS #7 127-793/30

Energies yielded as a "pop-gun" with Vortek piston seal:
-The Maccari XLD spring 120-775 yielded on a first test:
10.7 ft-lbs.- JSB/7.33
10.5 ft-lbs.- JSB/8.44

- The Vortek spring 113-780 yielded:
9.0 ft-lbs.- JSB/7.33
8.7 ft-lbs.- JSB/8.44

-The Vortek spring 118-745 yielded:
9.4 ft-lbs.- JSB/7.33
9.0 ft-lbs.- JSB/8.44

At this point in time, it became clear that the swept volume was not enough to reach much higher energy levels
We should also note the incredible versatility of these little rifles. With a 0.113" WD spring they can be perfectly setup for any young/small framed shooter with little upper body strength and still yield around 8 ft-lbs
With "stronger" WD's it becomes a respectable performer that will be perfectly legal under UK law.

Since the owner wanted to compete in FT, a minimum of 11 ft-lbs was deemed logical.
Yes, it is true that many championships have been won at 10.5 ft-lbs, but these are champion shooters that have extraordinary abilities in wind-gauging and range-finding; for "mere mortals" a minimum of 11 ft-lbs is a logical starting point.
AND, you need to remember that this is a breakbarrel rifle.
Also, a new batch of JSB/7.89 arrived and so I decided to include them.

The "Mod"

In order to achieve a larger swept volume we decided to convert the piston to an ORing head piston and allow the maximum stroke / volume possible.
Once all the "travels" had been checked, it became clear that we could go as high as a 77 mm's stroke with no secondary effects on the cocking lever, or the piston's channel.
We ordered a new piston, just in case we needed it and it is pictured below side by side with an ORing head piston. IF the modification, for any reason, is not desired, we can swap back to the OEM piston without any problems, as no other part of the gun was modified.
The difference between the total length of the OEM piston and the CCA O'Ring piston is 4.5 mm's so the rifle is not completely "maxed out". I distrust things that are maxed out. But that is just me.
In reverse of my usual tunes that involve short stroking a larger gun, this is the "long-stroking" of a smaller gun.

Going from the Vortek seal to the ORing head piston, the added stroke added 39 fps / 0.4 ft-lbs to the yield of the gun with the 7.9 grs pellet.

The CCA O'Ring head piston can take any ORing of the specified size. However, it has been our experience that some ORing materials are better than others for each manufacturer. Meaning that the "harmony" between one material and the compression chamber it is working in depend on a number of factors; among them: steel, uniformity and finish. Differences in output can be substantial; as an example, between the worst and the best materials, the MV's varied between 750's and 790's (5.4%) using the same pellets, spring, guide, and tophat.

Having determined which material was the best for this case, we proceeded to center ourselves in the 7.89 grs. pellet, as it seemed to draw out the best characteristics of "Private HW50": best shot cycle, and best energy.

One thing we noted was that the little rifle tended to "gall" the front lower section of the piston and the high rear section of the piston (the asymmetrical wear described above), this started happening with the Vortek seal, so we installed buttons that stopped the process.
Just to clarify, this is not the same "galling" that has been described as happening on the OUTSIDE of the action via an excessively spaced "linear bearing" in the cocking lever.

Upon re-test with the 7.9 grs. pellets, we discovered that the Maccari spring had lost 30 fps on the first 100 shots, and was now yielding 10.4 ft-lbs
We spaced it up using one and then two washers that are 2.3 mm's thick (main reason why I do not want to start maxed out), but the power output did not increase at all for the 1 washer test, remaining at 10.4 ft-lbs.
And increasing only slightly to 10.6 ft-lbs for the two washers test.
It is clear then that, for the spring in question, the compression chamber had reached the maximum output possible.
Once we re-installed the Titan XS #7 spring, output came out at 10.8 - 10.9 ft-lbs
And so, we concentrated now on learning what was the best lube for this barrel.
For that, we tested in 20 shot strings, the performance of the 7.89 grs. JSB Exact lubed with T-9 and with baked Pledge.
Here is a scatter chart of MV's. Do note that the origin of the chart is 500 fps, that origin was chosen to be able to discern the small variances in MV with a 0 fps origin, the variances are invisible.

The statistics themselves are interesting:

As you can see, the lubricant used on the pellets had somewhat of an effect on the performance.
At 788.2 average fps for the 7.89 grs. pellet yields 10.9 ft-lbs which is real close to the objective.
With an ES of 13, BUT a SsD of 3, it tells us that there were some "rogue" pellets in the tin that pushed the ES, but were unable to spoil the sample Std Dev. beyond the 3 fps. (an advantage of the 20 shot strings). Do remember that in a proper "normal" distribution, the ES is ABOUT 3 times the sd.
For statistical sakes we use the Sample standard deviation, that penalizes even further the number.

And, it could also be a question of the whole system "settling down".

We'll see what happens in the second part of this "Boot Camp" when we test for accuracy

So, keep well, shoot straight, and stay tuned!

HM

8 Comments

FT rifles for small frame shooters

10/29/2023

9 Comments

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

9 Comments

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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