In a single-piece rifle stocks, the butt also differs in designs involving the "European" type, which has a fall for the heel to favor quick shooting making use of iron sights; and "American" style, which the heel stays horizontal in the grip to favor more precision-oriented shooting applying telescopic sights. https://gun-stock08417.verybigblog.com/26575400/the-best-side-of-shot-gun-stocks