Wagria recoilless air pistol patent

[DrGunn]

I first came across this patent whilst looking for something else in the vintage gallery, but I was intrigued and followed the trail back to a thread on here from 2019: https://www.airgunbbs.com/showthread...-experts/page2
I was looking for a new project at the time so decided to have a go at making one from the limited information available in the patent drawings:



It took a fair bit of head scratching to develop a design which could assembled and disassembled easily - I thought this would be important, as making it all work would take a fair bit of tinkering and adjustment. The power plant consists of a single cylinder and two matching pistons, each driven by half a Webley pistol spring. The spring guides are threaded to hold them into the cylinder. The cocking arm pivots are attached to a sleeve which slides on to the cylinder, the breach block bolts on to the sleeve at the front and through the cylinder into the trigger assembly at the back:



The trigger mechanism proved to be quite fiddly and still needs a bit of refinement. I added more adjustments than shown in the patent as I concluded that adjusting everything so it worked would be challenging - I was right!



Once I eventually got all the bits ready I discovered that it was very difficult to adjust the trigger to make both pistons release simultaneously so I made a temporary cutaway side plate so I could see what I was doing:



Once adjusted correctly the side plate was replaced and the gun fully assembled. The grip is carved from a scrap of Cherry to match the shape shown in the patent. The assembled gun:



And cocked:


The loading port is a bit larger than the patent showed - I though that having made a recoilless air pistol, it should be able to shoot pellets instead of BBs. The loading port to viewed from the top:



And cocked:



There isn't any form of anti beartrap so it is best to hold the cocking lever back whilst dropping a pellet in.
The shot cycle is not completely recoilless like the Diana model 6, at least partially because it could so with some more adjustment and refinement. It seems to be fairly powerful although I haven't measured the muzzle velocity it yet. I still need to make the sights so haven't done any accuracy testing and I will need to finish the metalwork at some point - this may all take a while yet though.

[Mark D]

I am massively impressed !! Well done

A compact over lever design - is it .22 or .177 ?

[ccdjg]

Lovely work Matt, and obviously a much greater mechanical challenge than the first appearance of the patent drawings might suggest. I will be fascinated to see what the final performance results are like, and what shot-to-shot consistency this mechanism is capable of delivering.

Another contender for one of Matt's (ptdunk's) videos I would say!

Cheers,
John

[Garvin]

Amazing work, Matt! It sounds like quite a successful design from your initial test...

An effort worthy of something from the Griffiths patent creation stable and you can't say higher than that.

[Benelli B76]

Very nice machining work there. John Whiscombe made some lovely opposing piston rifles, highly prized by many for their quality build. Also of course are the Park RH91 and RH93 rifles which were virtually recoilless.

Baz

https://forum.vintageairgunsgallery....ark-rh91-rh93/

[IMG][/IMG]

[DrGunn]

I am massively impressed !! Well done

A compact over lever design - is it .22 or .177 ?

Thanks! It is 177, I think the barrel an offcut from a Diana.

Lovely work Matt, and obviously a much greater mechanical challenge than the first appearance of the patent drawings might suggest. I will be fascinated to see what the final performance results are like, and what shot-to-shot consistency this mechanism is capable of delivering.

Another contender for one of Matt's (ptdunk's) videos I would say!

Cheers,
John

Thanks John. Yes it was much more complicated than the drawings made it look, a lot of this is because I made it easy to disassemble though - a Diana like spot welded production design would have been much simpler.
I'll update with performance figures as I progress with refinements and testing.
It would be very interesting to video it with a high speed camera - especially as the position of both pistons can be seen at all times.

Amazing work, Matt! It sounds like quite a successful design from your initial test...

An effort worthy of something from the Griffiths patent creation stable and you can't say higher than that.

Thanks Danny - high praise indeed!
Yes I'm very happy with this for a first test but there is definitely room for improvements.

Very nice machining work there. John Whiscombe made some lovely opposing piston rifles, highly prized by many for their quality build. Also of course are the Park RH91 and RH93 rifles which were virtually recoilless.

Baz

https://forum.vintageairgunsgallery....ark-rh91-rh93/

[IMG][/IMG]

Thanks Baz. The thing that is unique about this twin piston air gun is that the pistons are not synchronised. The Diana Giss and Whiscombe guns both use gears for synchronisation and the spring pressure and chain link on the Park provides a similar function. In the Wagria design there is nothing linking the pistons, the trigger sears must break at the same time and the two power plants must be very well balanced if it is to work correctly.

[ggggr]

That looks a nice job Matt.
I thought that about the sears and pistons, if not spot on, or with wear, it will throw out the timing of one of the pistons. In a way, it's a pity that you have not made up another slightly different sear to see how badly it would change the smoothness of the gun.

[DrGunn]

That looks a nice job Matt.
I thought that about the sears and pistons, if not spot on, or with wear, it will throw out the timing of one of the pistons. In a way, it's a pity that you have not made up another slightly different sear to see how badly it would change the smoothness of the gun.

Thanks Guy. I don’t think the sears are quite right as it’s is - this is where a bit more fettling should balance things out. If the springs aren’t quite the same this will have a similar effect, I may be able to balance a small mismatch in the sears with washers behind one of the springs.

[micky2]

Amazing work, Matt! It sounds like quite a successful design from your initial test...

An effort worthy of something from the Griffiths patent creation stable and you can't say higher than that.

I could not agree more with the above statement. a great piece of skilled work. and another one done from original drawings. it is nice to see just how these would have proformed if gone into production.

[junglie]

Amazing well done!

[Garvin]

Matt are the piston heads fractionally short of touching each other when at rest? Presumably you'd feel it if either travelled a bit too far?!

[DrGunn]

Matt are the piston heads fractionally short of touching each other when at rest? Presumably you'd feel it if either travelled a bit too far?!

No the piston heads come into direct contact with each other at the end of the stroke, the challenge comes in making sure they meet in the middle of the cylinder. I’m not sure at what point in the stroke the pellet leaves the barrel, it’s entirely possible it has gone before the pistons reach the centre.

[Garvin]

No the piston heads come into direct contact with each other at the end of the stroke, the challenge comes in making sure they meet in the middle of the cylinder. I’m not sure at what point in the stroke the pellet leaves the barrel, it’s entirely possible it has gone before the pistons reach the centre.

Fascinating! I won't ask any more questions until you have had a chance to test it more thoroughly.

[Powderfinger]

Exceptional work. Great to see a piece of lost shooting design brought back to life.

[eyebull]

Incredible stuff, can't wait to see more on this.