Canadian Airgun Forum

OK,, so if the brits consider 12 ft lb,s and over, full power, then I reached it. The single stroke pneumatic gun Wayne ( AKA Watertown ) and I have been designing and building for the past year, has reached its goal of 12 ft lb,s. Actually 12.29 ft lbs to be exact. A crosman hp 14.4 gr pellet, soared across the chrony today at 620 fps. I fired about 30 shots today, trying this and trying that, and for the most part I averaged 596 fps, a couple at 610 And 612 and then it happened. 620 fps. BUT then the gun broke. Not broke really. theres a stop bolt in the rear of the gun that stops the valve stem from going through my face. anyway, the threads stripped out. So to prevent it from happening again, Im going to make a new bolt and rethread, then thread 10 32 bolts through the side of it. Plus a solid aluminum end cap 1/2" thick with 4 x 1032 bolts in, it. So no chance of getting a bolt in the face. Anyway. Its still not ready for pictures or video. Still a few issues to work out. Stay tuned.
PS. By the way. I can pump it with my arms out stretched. About the same as a Daisy 953. In case you were wondering.

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If I had only one wish, it would be to be able to "unsay" things.

Sounds interesting, looking forward to seeing pictures

Nicely done, Joe.... 12 FPE is the most you can use in a rifle in the UK without having an FAC, so that is why they concentrate on that number.... It's "full power" without a license (ie if you stay under 12).... There is a big discussion over on the Yellow right now, a few guys are trying to build 12 FPE SSPs, but they can't even make up their mind what an SSP is.... Some say it's one PISTON stoke, but you can us a ratcheting mechanism to push the piston (requiring multiple strokes), or a lead screw to compress the air.... The opposite end of opinions is one compression stroke, from empty, with all the air vented (which I think yours does).... In between, we have Retained Air (Air Conserving) Pumpers, with a check valve, where the valve might have 1500 psi in it, but only dump a small amount, like a PCP.... with the idea being that if you only put in one stroke for each time you fire it, and it's tuned right, it's an "SSP".... Then there is the idea of a setup like the Webley Paradigm, which uses a stack of Belleville washers and a piston to maintain constant pressure for part of the firing stroke.... or a gas piston to do the same thing.... some with check valves, some without.... It's causing quite a flap....

My vote would be one stroke of the LEVER (round trip, open and closed) giving 1 shot.... period.... however you make that work.... but then that leaves the question of using a spring (steel or gas) to store (some of) that pump stroke (like a springer).... I guess it's not as simple as you might think, right?.... Is the Webley Paradigm a pneumatic, a springer, or a blend?.... Sorry, I shouldn't have brought this up, kind of off topic.... me bad....

Yours appears to be about as "pure" an SSP you can get.... so congratulations on accomplishing your goal....

Bob

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Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal; Too many! Springers, Pumpers, CO2, but I love my PCPs and developing them!
Proud Member of the 2000+fps Club!

Thank you so much Bob. I am so pleased I was able to configure this. To me, its amazing. The secret is the valve and trigger, which for now is a secret. I hope to be able to do a video soon, with visual proof. I know there are skeptics.

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If I had only one wish, it would be to be able to "unsay" things.

Very impressive Joe. I know you do good, honest work, so video 'proof' will just be icing on the cake. Really looking forward to seeing how this rifle looks, what sort of aesthetic you put together for the finished prototype. The finished weight will also be interesting. Of course commercial development could turn out very different looking, but as mostly a design-on-the-fly sort of guy myself I can learn a lot about how someone else thinks by looking at the results. Not that I expect you to give away your secrets! A years' work on this thing should earn you some fair return. And 12fpe for an SSP is a heck of an accomplishment.

Some of the impressive features are. Without a stock, it weighs close to 6 pounds. So stocked and scoped, it should come in around 9 pounds. Thats more than I'd hoped, but still not real heavy. Secondly, theres no hammer. Third, it cock,s itself after every shot. Just pump once, load and shoot. Forth is how easy it is to pump. As I said, Im a sixty yr old out of shape guy, and I can pump it with arms fully extended. And, depending on how much pump stroke you use, you can shoot with less power. Parts are easily accessible for replacement or repair, however most , well nearly all the parts are custom made. However the o ringa are of the shelf. The prototype is made of aluminum, but a production model should be steel to slim it down. It looks kind a bulky as is.

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If I had only one wish, it would be to be able to "unsay" things.

Sounding very nice Joe. If your worried upon your rear cap. Just remember 1.5× bolt dia for tear out area.

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May the cry of the pack be with you upon your hunt

Whitewolf

what does that mean exactly.

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If I had only one wish, it would be to be able to "unsay" things.

He means you should allow a minimum of 1.5x the bolt diameter between the rearmost bolt edges and the rearmost end of the tube, to avoid tear-out.

It means the center of the hole should be at least 1.5 times the hole diameter from the end of the tube so that the screws can't rip through the tube and tear out.... It's a general rule of thumb, and the actual distance required depends on the thickness of the tube and the loads on the screws.... Basically you want more material past the hole than the width of the hole itself, so that the tube wall will compress around the screw/pin before it rips out the end with no warning....

Bob

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Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal; Too many! Springers, Pumpers, CO2, but I love my PCPs and developing them!
Proud Member of the 2000+fps Club!

Oh, OK. well theres no pressure on it. Just the pounding of the valve stem as it flies back. Its fixed now, and should not be a problem anymore. Its amazing how much force is exerted by a small piece of metal travelling only a half an inch. I wish I could measure the pressure, but the gauge itself would cause a false reading by the air used to activate it. But according to the measurements, it,s around 1800 psi.

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If I had only one wish, it would be to be able to "unsay" things.

Congrats on your accomplishment, Joe. Anxious to see your reveal.

Congratulations, Joe -- and Watertown, too. A 12 fpe SSP is very intriguing.