Did you know pump shotguns can jam?
Sure as the class they are more reliable than semi autos, but no mechanical device is 100% reliable all the time, forever .
Today I had a jam shooting two and three-quarter inch shells out of a 20 gauge Mossberg 500.
I pumped it carefully and hard; I did not short stroke it. The muzzle was aimed up at a very sharp angle skyward when I did this though .
The round you see in the action was NEW ROUND, live, jammed nose down; it would not come loose from shaking the gun even rapping the butt on a tree stump.
I had to pry the shell out with my pinky finger .