Yes Ted, once I dropped a stray 16 ga shell into a 12 ga gun during a flurry. I neither dropped a 12 ga shell on top or it nor tried to close the gun. If this is the best you can do, give up.

You know what you know (French guns) but you don't know anywhere nearly as much as you think you know (a fact which you have been proving by demonstration on bulletin boards for, oh, what 8 years?).