I have a Mossberg 5500 semi auto 12ga. It has been to the gun smith twice, I replaced all the seals and springs and it jams EVERY SHELL. I also had a pump, I don't remember the model. That thing cycled shells like it was full of sand. They were cheap but you get what you pay for. I Haaaaate Mossberg. The Remington 870 and 1100 are much better guns and I have never had either one jam. Maybe some of the higher end Mossbergs are OK, but I will never buy another one.