Multi-lug breech mechanism

摘要

A breech mechanism embodies a multi-lug sliding breech block having a plurality of pairs of lugs. At the instant before firing, the bearing surfaces of at least one pair of lugs are spaced a predetermined distance apart from the bearing surfaces of the respective threads, or lugs, of the breech ring. When the cannon is fired, a reactive force acting on the breech block elastically deforms the material of the ring and block, forcing all the bearing surfaces into an abutting contact relationship whereby the stresses produced within the material of the mechanism are more uniformly distributed throughout the breech ring and the breech block thereby increasing the service life of the mechanism.