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A BB gun for the US Army                                                      ©

12/21/2022

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This is a long story, but I'll try to make it short.

It all started about a year and half ago when I received a somewhat "peculiar" question from a person that signed his Emails as being part of "Small Arms Dev-Com/US Army"
And the question was peculiar because they asked if I thought that a Daisy Red Ryder could be powered up to shoot steel BB's at 690 fps.

¿HUH?!!!

OK, this merited some research!

As with any other customer, I got in contact with the young man and tried my best to find out what they really needed.
Because I knew what they wanted: A Daisy Red Ryder capable of shooting steel BB's at 590 FPS and that wasn't going to happen!
After some EMails were exchanged I understood the need.

In essence, these are the guys that CALIBRATE the gel blocks used for terminal ballistic testing.
To calibrate the blocks they shoot BB's at them, every shot gets chronographed and the penetration has to fall within certain parameters for the block to be "acceptable" for testing.
So, not only do they need to shoot the BB's at 590 FPS, but they need to keep to a Std Dev of 15 fps.
Once the gel blocks are calibrated then they get shot with serious stuff or form part of the safety equipment testing procedure (helmets, goggles, gloves, vests, chest plates . . .)  everything gets tested with the "real thing", but that "real thing" needs to be tested in calibrated gel blocks. A sub-standard Gel block might give "passing grade" to a piece of equipment that can end up being dangerous to our guys in the field.

Now, from my experience in the pellet rifle world I thought that would be a piece of cake.

¡HA!

The Std Dev. proved to be the harder spec to meet, but we're getting ahead of the story.

So, coming back to setting up the project specs, I sent them a communication stating that there would be two possibilities: a spring gun (just not a R-R), or a PCP.

We analyzed the advantages and disadvantages of each powerplant, and originally, it seemed they had settled on a sidelever, I even tested an SPA SR900S sidelever to see what sort of MV's we could get, but then the ideas changed. It so happens that the system they were using was powered by Dry Nitrogen, and so the supply of compressed gas was absolutely no problem.

So, a proposal was made and sent.

Some months passed and I had already thought that the project had fallen through, but then I got a request to "update the proposal". OK, so got that done, and sent.

Some more months passed and another request came in for an update. Got it done and sent.

After some months had passed I was not really expecting anything when I get an EMail from a different person. Telling me they needed to submit the project for funding. That they needed a formal proposal.
OK, so I drafted a two page sheet with terms, conditions and specs, and sent it.

Some more months passed, and then I get an EMail from someone asking me to take a third party liability insurance for a Million Dollars. She also sent the full "Legalese" package.

As a gunsmith I am, above all, pragmatical, and if that was the ONLY way to do business, well . . . . Thanks, but no, Thanks.

And so I communicated what would be acceptable to CCA: I would deliver the system and provide all the information for safe operation. When the system had been tested, approved, and the technical personnel had signed off on the equipment as "fit for duty", then I would collect.

Some more "Legalese" was exchanged, and we finally agreed to a framework. To their credit, it was easier negotiating with the Army than with some construction contractors I know.

And then came a "purchase order". All formal and nice. With the request of some tax forms! . . .  WHAT?????

Quick call to my accountant and then to my contact at Dev-Com and it resulted in a simple print-out of a form issued on line by the IRS. Phewwww!

At every step, my wife kept asking: "Are you sure this is all about a BB gun?" LOL!
And yes, I had to admit that it began to sound more and more "barroque".

But I decided to toe the line and get everything started.

The Build

After much discussion, we had settled on a DIANA Stormrider, black, 2nd Generation.
We would install an Altaros vented regulator, and a custom Lothar Walther smoothbore barrel.
We would tune the gun to shoot to the required speed using the techniques we developed many years ago.

Orders were placed for the parts, and within a week, parts started to arrive.
Pyramyd Air delivered the Stormrider
Altaros delivered the vented regulator
 
And we waited for the barrel.
Just two weeks after, the barrel arrived.
Wow!
​
So, now chips could start flying!

First was the disassembly of the OEM rifle, and "presenting" the parts available:
Picture
After the regulator and the additional manometer/quick-fill were installed, we tested for leaks by pressurizing the air tube and letting it rest for a week.
​Meanwhile, we took the L-W smoothbore blank and turned it to fit the action:
Picture
Then the TP and a cavity had to be milled. The cavity would house a magnet that would hold the BB just in front of the point of the probe:
Picture
ORing grooves cut and a bit polished, the barrel went into the gun:
Picture
Action was presented and semi-assembled:
Picture
Variable, self-blocking TP was installed:
Picture
And gun assembled:
Picture
Picture
And then we tested.

WHAT A DISASTER!

With the initial calculations pointing to the idea that we should be getting about 12 ft-lbs, the gun yielded 1,016 ± 22 fps Not only too high, completely unacceptable from a regulated gun.

And so, we reduced the TP diameter.
And reduced it.
And reduced it.
Once we reached the 1.19 mm's, we could not reduce that anymore, and MV was still at 616 ± 75 fps
Hmmph!
Something was tricky here.
And I started measuring the BB's.

What I had obtained as "Precision Ground Shot" had diameter differences in the 0.0025" region.
Got another lot . . .  same thing.

Then I spotted something Daisy calls "Premium BB's"; hmmmm . . . . let's try those.
MV came out at 
623 ± 16 fps
Good; now we're cooking!


Since PCP's are nothing but mechanical amplifiers, I thought: "let's reduce the input signal".
Clipped one coil from the hammer spring , output came out to 649 ± 13 fps ¿¡Huh!?
So, we clipped and clipped the hammerspring till we were getting an MV of 587±10 fps

We let the project rest for a week and took a 30 shot string every hour
@ 11:30 .- 583 ± 16 fps
@ 12:30 .- 587 ± 13
@ 13:30 .- 585 ± 9
@ 14:30 .- 583 ± 12
@ 15:30 .- 587 ± 13

I sent the results of the tests to my guys and back came a question:

"If, for whatever reason, we need to change the MV, how do we do it?"

Aaaarghh! I should have seen than coming from the start! 
IF (big if) I had known the wide variation in the diameter of the different productions of BB's, I would have, but I was ignorant of that.
And now, I was going to pay the price.
If negotiating the initial "contract" had been difficult, getting a "change order" would be even more. So, chuck it to experience, and service to the country.

Back to square ONE.

Because of the nature of the projectile, the small differences in diameter really throw a wrench into any calculation you might come up with. On top, the fact that there is no rifling means that the projectile is Ultra-Efficient in absorbing energy from the powerplant. No energy is taken form the shot cycle to "swage" the pellet to final shape, and virtually no friction means there is no energy lost there.

I considered a number of solutions but, in the end, settled on doing something that I should have done many years ago: design a free flight hammer system for the Stormrider. Back then, the results obtained by changing the TP were deemed more than acceptable on all grounds: efficiency, uniformity, consistency, and simplicity.

This project was different.

We procured the new hammerspring (because a FFH only makes sense if you start from a full hammerstrike and then reduce the output in a metered way).

We had to reset the regulator, re-do the TP adjusting, and recommence the whole testing protocol.
The stock in the SR had to be modified to accommodate the FFH device, and this posed another small challenge; as the SD's were inexplicably high, we first re-checked the whole pneumatic section but, in reality, it was a simple, intermittent, mechanical interference problem.

By the end of the 12th adjustment/setting. we finally settled nicely on a string of 30 shots that gave 592 ± 12 fps and then another 30 shot string of  585 ± 14 fps

The gun yields 4 strings of 30 shots at these power levels between 230 Bar's and 115 Bar's, though we recommended refill after every 90 shots.

 And so, the gun was shipped to Picatinny Arsenal, and the reports so far is that the system is working "great".

The future

Yes it was a complex project, we learned a lot and it opened our eyes to an avenue of research that no one had gone into recently: Smoothbore barrels and their projectiles.
Airguns do not achieve the hypersonic MV's that some current military designs require to work well, but there are alternatives, and the new technology to "turn" lead makes for a VERY interesting duo.

We will follow a bit this development because it truly is an interesting avenue that I hope will garner some interest from the industry.
​
The next smoothbore L-W barrel is here... ;-)
Picture

Closing thoughts

I am very proud to have been able to help our military, even in the minuscule way we did.
The fact that, perhaps, some safety equipment will help keep a soldier safe in the field due to the thorough Terminal Ballistic Testing that the Army puts the protective equipment through is a matter of consideration to me.
And, it was really a pleasure and a privilege to deal with technically qualified people. Would love to meet them one day, but as with many friends in this airgunning world, I know it's going to be hard to meet them in person.


AND I need to add that without the support from great companies like DIANA, Lothar Walther, and Altaros Air Solutions, this project would have been MUCH more difficult to tackle properly.

To all our readers, thanks for one more year of your time and attention, we wish you all the very best of the Holiday seasons, do not eat too much Ham, nor drink too much Eggnog, and remember that everything is better in moderation . . . even moderation itself!

;-)

Ho Ho Ho!






HM
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The importance of PROPER lubing                                       ©

12/6/2022

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Every now and then someone asks why I insist on proper lubing.

Another common question is: "¿What IS proper lubing?"

Still some others that think that offense is the best defense, ask: "Why do you lube your pellets? I shoot them straight out of the tin!"

;-)

Fair enough, we all know that each rifle is different but, still, in my years of professional gunsmithing I have found two basic "truths" that apply in airgunning:
1.- Pellets fly best at or below the 875 fps region
2.- PROPER lubing of pellets AND rifles DOES make a difference.

Perhaps in some guns the difference is small enough that it is impossible to measure, but IMHE, there is always a difference.

My mind follows very peculiar paths; "tortuous" would be the word chosen by my wife, but I prefer to think that I am always looking at all problems, sometimes simultaneously, from different points of view. Just part and parcel of being a Gemini, LOL!

In any case, as a pre-requisite experiment to a new design of piston that I need to tackle a complete "re-do" of some military replicas, I wanted to start by testing the new design in a well known platform. Normally, at this stage I would start looking into the classifieds and the whole thing would take some time but, luckily, I had already sourced it some months ago and that was covered. And no, it is not a DIANA.

All good experiments start by laying a "baseline". A point from where all other comparisons are going to be set-up, and so I proceeded to test the gun, after being in storage for some months.
Starting with a good 20 shot string just to bring the gun back to "operational" status, I started chronoing pellets that I knew usually shot well in that brand of airgun.
They are reputed to have bores on the "generous" side, so the first pellet chosen was the JSB Exact 8.44/4.53
As an aside, here I have to remind everyone that the numbers stated for the head size, in the case of JSB, are not exactly measurements taken from the heads of the pellets, but rather obey an indirect method of measuring where they test  in different barrels and then assign the head size of the barrel that shoots them best.

I also added to the mix the H&N BFT, both in 4.50 and 4.51 head sizes. My experience is that the head weighs enough to be "upset" by the pressure blow and have a good contact with the rifling.
My DIANA guns (54 and 430L) prefer the 4.51 size, but some other guns prefer the 4.50

Finally, I added the QYS pellets that have been taking most of my time lately. Very uniform, and accurate when the bore likes the land-riding design of the head. Of course, creating a land riding pellet starts with the premise that people know that the design is handicapped in the power it can take. We'll get to that later.

So, all in all, 5 pellets that I consider the best among the current production runs.

AND then I started taking apart the "test mule".

Horror of horrors!

Gobs and gobs of black tars of different densities and viscosities.   :-P  Dughhhhhh!

It was going to take 3 hours to clean this mess!

But then, looking at the other side of the problem: ¿WHEN would I EVER get a better chance to test what has become the "traditional American grease tune"?

I was not going to do one of those tunes, LOL! .

I do not even have those heavy lubes at hand anymore! It's been YEARS since I stopped using those heavy petroleum derivatives. Paraphrasing a friend "That's dinosaur juice!"

So I closed again the gun, and got the pellets out to create that "baseline".

And a lightbulb flashed in my head: If I am going to compare lube jobs, why not compare also pellet lube jobs?
And the 5 became 7.

The test was simple enough once all the parameters were laid down, we would look at MV and KE of the 7 pellets chosen with the "grease" lube-tune and then clean the whole thing with lacquer thinner, and re-lube with Ultimox 226.

Because we had pellets with different leads and different lubes three shots were allowed between each change of lube, and 5 pellets between each change of lead. And then 10 shots were taken for the record for each pellet.

I did find that the pellet lube was a more important change than the change of pellet lead. Which is an interesting conclusion in itself. Many shooters believe that you need to completely clean the barrel and then take 20 shots with each different type of pellet you test, what I have found over the course of years, is that if you lube your pellets you need to worry more about change of lube than about the change of pellet/lead itself.
I have also found that most bores exhibit a definite preference for certain lubes. I used to use three lubes, but for a few years I have only used two now: Pledge and T-9. Both products that come from the non-shooting world, are inexpensive and widely available, and hold no "secret sauce".

Well it was a rainy and depressing day anyway, and I had just delivered a project to one of our Armed Forces, so I had the time before tackling other projects.
I shot the full 100+ shots test with the "Traditional Lube", and then spent, literally, a couple of hours cleaning that stuff, then re-lubed with Ultimox 226 and ran the whole test again.

And, here are the results:
Picture
So, how do we analyze this?

For starters, you can see that for identical pellets in the same rifle, under the same conditions, the difference in lube can mean between 2 and 8 fps in the case of the "dinosaur juice" lube-tune and between 2 and 5 fps in the case of the Ultimox lube-tune. In both cases, the fact that the difference was smaller for the H&N 4.51 pellets, tells me that we should try to achieve maximum accuracy with those pellets from the H&N family.
We can also notice that this bore seems to prefer the Pledge lubed pellets.

Some may say: 2 to 8 fps is not worth the work to lube pellets. While that is true from the energy standpoint, when you look for maximum precision and accuracy, those 2 fps can mean that the harmonics in the barrel "jive" to a good tune or produce a cacophony. Many times have I found that a harmonics tuner tuned to a "naked" pellet needs to be moved a tad when the pellets get lubed. And that some bores that "do not want to shoot" as the user wants, in reality are just asking for the pellets to be lubed to start shooting up to snuff.

Now, if we move ACROSS the lube-tunes of the SAME GUN, there are other things we can conclude, and basically, it's that if you are still using the old lubes, you are leaving a LOT of energy on the bargaining table. In other words you are not getting the efficiency that you COULD be getting, at least in a finely crafted gun like the one on the experimentation table.
Kinetic Energy gains of between 15% and 22% are nothing to sneeze at. And if the "quality" of the shot cycle was about the same, lowering the Ultimox tuned rifle to the same energy level as the Dino-juice tune, will certainly enhance the quality of said shot cycle. In brief: There are less inefficiencies that go to produce twang, vibration, heat and other residual energies (like noise) when using Ultimox.
​
Now, while some GAINS are impressive, you still need to consider which pellet will yield the best result at the target, and that is something we will be exploring soon.

Prime candidates for testing, especially at longer ranges would be:
H&N BFT both head sizes, as well as the Heavy QYS domed all lubed with Pledge, need to be tested, also the JSB 8.44/4.53 needs also a thorough testing and a testing with Pledge.

We can safely assume that the QYS light Streamlined is simply a bit light for the increased power transfer, and so it is deforming in the barrel, and loosing all efficiency. This may NOT pass, once the total power yield has been turned down to the proper level for FT.

Anyway, now that the questions about lubing (pellets AND rifle) have received an answer (limited to a sample of 1, agreed, but at least it is more than what we had before), it will be up to each shooter to decide if a lubing job of their gun and pellets is warranted or not.
Picture
Precluding any misunderstanding: we need to clarify that there is no substitute to the performance at the target.
Getting a uniform MV with low SD's certainly is a requirement to have a good performance at the target, but it's not a sufficient condition. Let's hope the weather will allow us to test these pellets outdoors soon.
Once that is done, we can continue with the next phase of the development.

Keep well and shoot straight!



HM
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Changing caliber of a "Lawrence of Arabia"                DIANA 34 EMS                                                                         ©

12/5/2022

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Following on our "Unintended Coincidence" post, a friend with a LoA DIANA 34 EMS wanted to change calibers.
He was not happy with the 0.177" caliber as it seemed to be on the "loose" side and pellets fell when he swung the action closed.

So, we sourced a few barrels from DIANA and, while it took some time, I think the results are good.

Process is not complicated but it does require a specific order of operations.

You start by taking the action out of the stock, a simple three screw operation that we all know how to do.

Then you need to take out the rear sight and the front sight. Rear sight is no problem because the screws are visible. Just make sure that you do NOT loose the 0.5 mm's ball that creates the "clicks" in the rear sight elevation knob.

The front sight however, is a bit more tricky because under the visible "thread protector" there is a nut, and in the rear sight ramp itself, there is a grub screw:
Picture
Front sight assembly
Picture
Thread protector removed and nut loosened.
Picture
After the grub screw has been loosened, the whole ramp can come off.
So, now without the sights, we can start working on the action
Picture
Unlock the "knee" in the compound linkage and disconnect the linkage from the piston
Picture
You can now undo the main barrel block bolt/axle. Be sure to use TWO wrenches. Since there are Loc-Washers on BOTH sides, when "undoing" the bolt, you will feel it tightening and then releasing.
If the cocking linkage bothers you, now is the time to disconnect it from the block. There is a small grub screw on the distal end that "locks" this screw in place. Loosen that, and then remove the affixing screw.
Personally, it does not bother me so, I always work with the linkage connected.
Picture
You can even work with the rear sight on, but then you should be careful
Picture
And now you can slide the barrel block out of the forks.
Picture
There are two thick washers that provide for clearance between the barrel block and the forks. Those can be lifted with a strong magnet.
Picture
Now you need to insert a tool that prevents the barrel from rotating when you loosen the barrel locking castle nut
Picture
Using this special socket. And a 3/8" breaker bar, you give the breaker bar a good "Whack" with a plastic mallet
Picture
Once it has broken loose, you can remove it using any other socket handle
As in most gunsmithing that involves actions, it is best to set everything under tension and then "whacking" the wrench than to try to break the tightness smoothly. This is one of the more complicated things because it seems that you would need three hands. You don't, but you need to do it suddenly.
Picture
Once the castle nut comes out, it is easy to remove the breech seal/O'Ring
Picture
Using a PP/dead-blow hammer, you separate the barrel from the block
Picture
If you are just changing barrels, you just follow the reverse procedure to install the new barrel.
BUT, the truth is that now is the time to do whatever you want done to the barrel. From re-crowning to polishing the rifling with JB, or lapping the bore if you are so inclined.
Personally, I like to clean the barrels very well and then polish the bore and rifliig with JB bore paste.
In this picture you can see clearly, from left to right how the "exiting" pellets show less and less scratches and deformations as the process goes along:
Picture
From left to right: OEM barrel finish, then after a few passes with JB Bore paste, then after the whole treatment has been done.
If you think that the difference is purely cosmetic and wondering ¿"what does it matter if a pellet looks ugly when it comes out of the bore"? then look at the edges of the skirts:
Picture
The rougher edges always translate in a skirt that is more uneven.
 Every bit of lead scraped out of place, instead of swaged into a new shape of the pellet is a disturbing influence not only on the pellet exit from the crown, but also on the pellet path.
Shards left in the bore may adhere to the next pellet and create a "vane" that will send a flyer out of the aimpoint.

​This barrel was additionally re-crowned.

In the end, the work performed paid out.

What counts is performance at the target, and with the barrel's favorite pellets, it did quite well for a break-barrel in the 15 ft-lbs class:
Picture
Top group is 10 shots from the FT position at 15 meters (about 16½ yds) with a 4X scope, and the bottom group is also a 10 shot group, but with open sights at 10 m.

I don't know how it was shooting before, but I do know that any reasonable target at normal break barrel airgun range is in danger with this rifle.

;-)

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

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