I've got a nice 870 Wingmaster with one problem. When I shoulder the gun and fire, the pump immediately slides back. All other pumps I've used hold tight until you give it that little push forward and then pump it.
Is there any thing I can do to keep the forearm from sliding back?
Thanks
JW

I have the same problem but I'm sure it's from shooting high brass shell, slugs, buckshot, or turkey loads. It never happened whenI shot the 2 3/4 low brass cheap shells like you'd use for clay pigeons or small game.

Does the gun going off alone open the action? If not, it sounds like a well-functioning shotgun to me. I can't stand the ones that hang up on me (I've shot many Novas that did this), I like to have a fresh shell fast.

Designed that way for quick folow-up shots.