SpudFiles

After my cheap crossbow finally broke I am left with a nice handle and trigger system. I've attached my 4x20 scope to the picatiny rails on the top and i am going to modify it into a .22 air/pellet rifle. At first thoughts it was definatly going to be a small coax but i want the aesthetics to be reasonable so even though coaxials are quite compact i would want the to be servicable and that would involve using an ugly threaded adapter near the pilot. So, i might still have to go with the coax and make it sevicable at the end of the chamber.

Second problem, to reduce bulkiness, i would pilot it through a schrader and the crossbow trigger system can be adapted so a little rod can push the schrader pin. Then i realised that i would need a way to fill it up and that would involve having to slide the whole coaxial setup forward to gain access to the schrader.

So, stick with the original idea or try out a new valve? It doesn't necessarely have to be powerful just a simple and strong plinker.

Video shows the crossbow system:

[/youtube]

coaxial might be good, just add another schrader for filling and spring behind the piston and there you have it

make a small colax piston hybrid, it will make it much more powerful and you can link a pezo the same way you would the schrader.

edit, something like the second post in that link.

I have been thinking about making a .22 rifle for a LONG time, coax it´s the best option to me, but it is a problem to charge it. if you want to pilot it with a schroeder valve, the piston better be a o-ring seal one, but in that case you won´t be able to charge it unless form behind the piston or make a really good high sensitive self-close piston

Yeah, my piston is made of nylon and has O-rings.

make a small colax piston hybrid, it will make it much more powerful and you can link a pezo the same way you would the schrader.

edit, something like the second post in that link.

Never played with hybrids so i doubt i could ever get one to work.

More than one way to make a co-ax serviceable. If you've the tools, you can drill, tap and countersink screws through the tube and into an o-ring sealed plug at the rear.

The math to calculate strength requirements/safety factors for this fastener arrangement is pretty straight forward as well....which is nice.

IF, i had the tools, sure, it would of been finished yesterday.

qwerty wrote:Never played with hybrids so i doubt i could ever get one to work.

That's what I used to think, but it's not exactly brain surgery The key to a powerful small bore is pressure, hybrids can do this easily and in a very compact manner, without the need to fall upon HPA.

I concur with JSR, hybrids are easy enough, and the power you'd get would make it worthwhile.

And JSR, it isn't brain surgery or rocket science, it's always rocket surgery. Don't you know the proper scientifical terms?

Again, I'll recommend a hybrid, fueling is easy with syringes.

Nah, still don't like them, i reckon it will be unreliable and i still don't fully understand the fueling. I get mixes and all that, it's just something that's hard to explain without typing billions of pages.