My Remington 870 jams

[rubenstone]

Hello,

I’ve been having an issue with my 870. Sporadically when I’m shooting, I’ll have an issue where the pump completely locks up and I can’t eject a spent shell. I’ll fight with it for a bit and then all of the sudden it will pump like there was never a problem to start with. This happens with cheap Winchester ammo but it also happened with some Remington 00, and starts to happen after I’ve shot a dozen rounds or so.

I took apart the gun and I think I identified what’s causing it. The bolt can slide back and forth about a half-inch or so, and sometimes the hammer will fall under the firing pin. It gets stuck there and stops the bolt from moving back. If I wiggle the gun around enough I can get the bolt to move forward and the hammer to fall backwards enough that the bolt will slide back properly, and then I can shoot like normal.

Is there something wrong with the gun’s internals? Is the problem something else entirely?
Thanks in advance!