I was out with a Marlin 99M1 this past weekend and ran a few different types of ammunition through it- Wolf, Remington, and Federal Bulk. Each type of ammo ended up producing a dud almost once per magazine (8 round tube). Always had a hammer mark, but they just didn't go off. I know those aren't premium manufacturers, but is that typical of .22 ammunition or am I looking at a problem with the rifle itself? Maybe a hammer spring?