Looking for a part and i dont know what its called

[socoj2]

Its kind of like an actuator, but not.. THis would be flat and have a piston in it.. WHen Pressure is applied the Piston is pushed out very fast.

I need it to eject shells out of the chamber..Think of it like a gopher stick his head out of the hole really fast when pressure is applied and pulling it back when released.

[noname]

Pneumatic ram? Pneumatic cylinder?

[CannonBall]

Lool a flat piston?
I think its a pneumatic cilinder. just like noname said.. if got a pneumatic cilinder myself

[homedepotpro]

like the opposite of a solenoid?

[Fnord]

You mean like the hydralic cyliders you see on forklifts, bulldozers, etc? Only with a cylinder that uses air?
Can you draw us a picture?

Also..

I need it to eject shells out of the chamber..Think of it like a gopher stick his head out of the hole really fast when pressure is applied and pulling it back when released.

Pneumatic gopher removal- BRILLIANT!
Why didn't I think of that. Why didn't that guy from caddyshack think of that.

[socoj2]

MOre like the thing that pops out when a turkey is done.. but its run on compressed air?

[rednecktatertosser]

Like a tirepressure gauge, the kind that looks like a pen? I think it would still be considered an actuator.

[boilingleadbath]

You want a spring-return air cylinder.

Search mcmaster for such.