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]
I visit occasionally to make unrelated posts.