Mossberg design is very robust. they have two extractor to hold the spent shell tight when extracting. The biggest thing is the feeder.....the one that lift the shell up to be fed into the chamber. It is not spring loaded like the Remington. That's where two of the 12 gauge failed and I had to return them. I never have a malfunction once on the mossberg. When your life depend on it, you need this kind of reliability.