Battery activation can be accomplished by a percussion primer, similar to a shotgun shell. Battery activation can also be accomplished by a percussion primer, similar to a shotgun shell. The .410 bore, is the second-smallest caliber of shotgun shell commonly available. The detonator was a 12-gauge shotgun shell filled with powder. Roll-crimping is traditionally used to close a shotgun shell containing a Foster slug. This was a paper shotgun shell filled with ballistite powder. Hanford developed a plastic shotgun shell that was popular throughout the 1960s. To use, one simply inserts a shotgun shell into the smaller diameter pipe. A shotgun shell can contain a single, large projectile known as a shotgun slug. A breaching round or slug-shot is a shotgun shell specially made for door breaching.