I always shoot at least one cap on an empty barrel to foul it before hunting or shooting. Because, I cleaned my ML last year real good, and loaded a powerbelt into it with 100 grains of pyrodex pellets. And, it sounded like a popgun went off!! To my amazement it didn't even make it to the big piece of cardboard 25 yards away! For the small cost of a cap it's good insurance!