I once made the mistake of shooting a hot dove shoot with an severely off face Beretta model 410. The gun stopped ejecting, then became difficult to open, and finally wouldn't open at all. That evening I took off the for-end to open the gun and noticed the bottom rib had come loose and developed a set of waves.

What had happened was the movement caused by the off face condition of the action had broken the weld holding the fore-end lug to the barrels loose. Mike Orlen put it right and I'm still shooting the gun today, but I won't shoot a loose gun anymore...Geo