Can someone please point out the problems with this?

[Benster]

I'm planning on making my own, single shot pellet gun. I have the idea for how I want to make the valve, but I wanted to get some feed back on any possible problems I might have with it.

The basic idea, is to drop the ammo into the open bolt, push the bolt all of the way forward so that the ammo is beyond the T-in, pull bolt back half way to slot (not shown in illustration) and lock down to prevent pressure from releasing from rear. Open valve (also not shown) to release pressure.

[Pilgrimman]

I don't see any huge problems, but you might want to use o-rings on the bolt for a seal, and to grind the tee down SLIGHTLY so that the ammo doesn't catch on it when it is pushed forward. You should wait for some more opinions though.

[jrrdw]

Whats to keep your ammo from dropping into the chamber when you push it forward?