I've asked around a bunch, and today shot trap with a guy using an 870... The 870 action stuck closed after a shot at one point. The cartridge had been discharged, But the pump wouldn't come back 'till the gun was stock-bumped on the ground (Keeping the muzzle safely down range the whole time, of course). I've never seen the Mossberg jam up or malfunction in any way. I'm buying one next week.