With heavy recoiling slugs they will do that.
Cycle it without shells, and you will find that after pulling the trigger you have to push the for end forward-you will probably hear a click-in order to make the pump cycle as if there is another shell in the magazine.
What happens with a heavy recoiling shell is the recoil moves the shotgun back into your shoulder. However, since your hand is on the for end-the pump-it is kinda held in one place while the rest of the shotgun moves rearward. In essence it is being pushed forward as occurred when you cycled it while empty.
You come out of recoil and the body moves forward some, while the hand on the pump again stays more stationary. The total result is you start to pump the shotgun without really trying.
Happens all the time with shells that have a lot of recoil.
Last edited by battue; 04/02/14.
