Smith & Wesson K Frame Bolt Assembly - Model 18 - Used - .22 LR 134 aluminum M&P 45 Full Size (M1

M&P 45 Full Size (M1

So if there is no model number then your revolver may be older than 1957-58

M&P Trigger Pin Headed - 9mm/

38 Special +P

Smith & Wesson K Frame Bolt Assembly - Model 18 - Used - .22 LR 134 aluminum M&P 45 Full Size (M1Factory OEM Smith & Wesson K Frame Bolt Assembly Part Number: 134 Compatibility: K Frame Model 18 Caliber: . 22 LR (Rimfire) Condition: Used Frame Size: K Frame Type: Complete bolt assembly This is an authentic Smith & Wesson factory bolt assembly (also called a cylinder stop) for K Frame Model 18 revolvers. The bolt is a critical timing component that locks the cylinder in proper alignment with the barrel for safe firing. Features: Genuine Smith &