question

[colty-bear]

i am working on my first piston and i am making a coaxial
will a piston shoot back if the piston is the same size as the inner barrel?
If the piston is a cm bigger?

[cannon monkey]

for what i been told if the piston even a little bigger it will move back but i only made 1 piston so see what the others say about it

[colty-bear]

well i guess it isnt my first piston i started my other first
i am making it into a paintball m203 coaxial

[cannon monkey]

well for what i know it should work but i attempted a coaxial last night few pipes and a pen i had laying around couldnt get the thing to seal right so ya...

[colty-bear]

yea also i have another question i am making a rpg
and i am going to have a 1 sprinkler if i modify it put a tee and a lever valve in one hole and a shrader in the other will i be able to fire and fill from the tee?

[ckman]

yes you should be able to because i have seen cannons that fill from the top of the sprinkler valve

[colty-bear]

thanks i cant wait to finish my paintball rpg

[mark.f]

Well, one thing on filling from the top of a sprinkler valve. The BudGun I made a while back used this method, and it was SLOW. There is a small filter which allows flow through the diaphragm as a sort of equalization hole. It allows a good bit of flow into the pilot area, but not a lot from the pilot into the inlet.

[MRR]

Do you really want to build your coax that way?

According to your first post it seems to me like there will be just a little to no space for compressed air in the chamber.

The barrel is inside the pressure chamber, the chamber is also the piston housing, so if the piston is as big as the barrel there is no space between barrel and chamber.

I don't know what design you have in mind but without more infos it sounds to me that it won't work very well.

[glass_05]

I agree with MRR, based on what you said I cant visualize this very well.
Please post some paint pictures of your design.

[colty-bear]

there will not be much air space i know but it is a cqb paintball m203
the sprinkler valve question was because i was talking about something else a paintball rpg
the piston is a little bigger than the 1 1/2 it fits snug in the 2"

is there a way i can put a shrader on the tank closer so you can fill it easier without machining it right into the air tank?