This is the genuine Crosman steel breech upgrade kit, Model 1377 SBPK.
Ideal for upgrading many .177 caliber Crosman air pistols and the 1760 air rifle, this kit provides a stronger breech and bolt assembly that enhances accuracy. It also features 3/8-inch dovetails for ataching a scope or suitable rear sight. The original rear sight supplied with these guns does not fit this breech, but the Archer Airguns Rear Field Sight for Crosman Pistols fits perfectly.
Contains the following parts:
.177 caliber bolt
Rear sight screw
5/64 hex wrench
.050 hex wrench
Fits many Crosman air guns, including the 1377, 1740, PC77 and 1760.