I hate to put them down as I know some of you guys like them but I've seen more failures to eject with Mossbergs than ALL other pumps put together. Kinda gotten to the point when I see someone with one on the skeet or sporting clays range I just expect to be held up while they get the empties cleared a few times. On more than one occasion I've seen us have to loan a Mossbery shooter a gun to finish so we could get on around.
I'd blame the gun not the shell if I were you.
GB