This P1 pistol won't take another round into its chamber. It doesn't have a magazine, and there is the icon saying that a bullet is in the chamber. But, the image for the gun itself is the 'out of ammo' image, and it won't fire.

I fixed the gun by clicking on the chambered bullet image, ejecting it, then rechambering. I have since been unable to reproduce this issue (22:23 EST, 7/8/2014).