METHOD OF PROCESSING RECEIVER INTERFACE AND END SURFACES OF SMALL ARMS FOR ENGAGEMENT WITH INTERFACE AND END SURFACES OF BOLT Russian patent published in 2014 - IPC B23B1/00 F41A3/66 

FIELD: weapons and ammunition.

SUBSTANCE: method involves mechanical processing of half-finished receiver with base preparation by lathe cutting of external diameter and drilling of a through axial cylindrical orifice for spark erosion and thermal processing of half-finished receiver at 710-720°C, ageing, tempering at 1000°C, and cooling. The encircling surface of the block undergoes spark erosion outlining bolt lug contours, half-finished receiver is annealed at 760-780°C or higher temperature in argon medium, and external diameter undergoes fine mechanical processing to ensure it is coaxial with the internal diameter of receiver. Further contour parting-off at bolt lug side, countersinking and axial orifice reaming follow to ensure slip fit for assembly with clamped bolt surface, then interface and end surfaces of receiver are grinded in with interface and end surfaces of bolt. Half-finished receiver is made out of martensite ageing class steel 03X11H10M2T.

EFFECT: enhanced shooting accuracy and small arms reliability.

2 cl