Bolster

A reinforced area that bears the flash or the barrel. On a flintlock lock, the bolster is the reinforced area on the side of the lock plate that bears against the side of the barrel. On the J.K. Hawken, the bolster is part of the breech, beside the lock where the hammer falls, and the nipple threads into it. The Hawken has an integral bolster. The Appalachian Barn Gun percussion uses a drum instead.