I don't completely understand this action but that's okay. Does the spent shell, partially out or not at all? If you do a search on the 870, you will see many posts on this problem. I'm gong to assume that your 870 is an Express. I know it seems like a big problems but work on it and when you get it out, check your base for signs of dragging or scribing. I know I had a problem with hanging on a burr at the six oclock location at the barrell breech. Good luck and please let us know how you made out.yesterday after hunting some coyote I put a spent hull in the chamber so i could dry fire w/o hurting the gun.
All breechloading rounds must swell during firing, to seal the breach end of the barrel. They shrink slightly when the pressure drops, but they will always be bigger after firing than before because they don't completely shrink.Shotgun hulls swell after being fired and putting one back in after cooling? i dont know about that one?