SpudFiles

This could work for bigger ammo like marbles.
The idea is to take a T with reducers on opposite end and put pipesections in there in wich yet a thinner pipe fits that can slide through easily.Make the pipe fixed in the reducer stick out on the inside of the T and provide seal to the inner moving pipe with a section of rubber tubing.
The inner pipe is the bolt/piston.It has an airhole outside of the pressurised T.It's pushed forward by a spring, but when not firing must fall into a catch, like on a crossbow.( not included in the picture)When the catch is released, the bolt moves forward and the opening is pushed into the pressurised T.The marble is loaded in this same action.When the bolt is pressurised the marble shoots out, the thickening of the bolt you see in the magazine T will act as a piston and together with the recoil begin pushing back the bolt all the way.As long as the catch stays released the cycle will repeat.Might take you some time to understand all this but I know it will work...Very little waste of air.

a marble size hole will let a huge amount of air out fast, how you gonna keep up that kind of airflow? but i think your bolt idea is pretty good, but your rubber gaskets to seal the but will probly jam the bolt,(rubber wont slide on plastic),work out that bug and i think it will work, good thinking

I only use metal.
If the bug is using PVC then start thinking out of the box....

I've tried the bolt idea but not in full auto and it works...less friction than a ballvalve if you open it by hand

if you could add some kind of pop valve in the air intake to slow the repete action down that would soulve the air comsumtion down to were a normal air compressor will work it

once the rubber o rings heat up they will allso stick to metal

use some kind of steel ring, like piston rings on a piston, that would take the heat and the pressure, and the pounding, problem there is were to get them that small, snap rings maby?

Or you could just use teflon "O" rings. Good for service temperatures up to 500*F.

Oh boy...I meant this to be used with a reservoir, not a compressor.
What good is a gun if it can't leave the compressor?!?!?!?!

If I can get 40 fullauto shots at 9mm I'm happy.I once got 8 or 9 shots out of a 22 mm pipe of about a meter long. at 14 bar.

Rubber is not gonna get sticky that fast especially if you lube it up.

wow that sounded kinky