bbqstorm

My Nova Pump occasionally jams. It has jammed on both dove loads(2 3/4" warm weather ) and duck loads(3 1/2" cooler weather). It looks like the new shell from the magazine tube is entering the chamber before the spent shell has ejected. Gun has been oiled well. I thought it may be that the pump wasn't getting pulled back fast enough but I have disproved that theory. I'd really like to fix it . Anybody got an idea? thanks