Smith & Wesson K Frame Hammer Block - Models 17 & 18 - Old Style - Used - .22 LR 18120

Factory OEM Smith & Wesson K Frame Hammer Block

Part Number: 18120
Compatibility: K Frame Models 17 & 18
Caliber: .22 LR (Rimfire)
Style: Old Style
Condition: Used
Frame Size: K Frame

This is an authentic Smith & Wesson factory hammer block (also called a firing pin block or safety block) for K Frame Models 17 and 18 revolvers. The hammer block is a critical safety component that prevents the firing pin from contacting the primer unless the trigger is fully pulled.

Features:

• Genuine Smith & Wesson factory part
• Old-style configuration for early production models
• Used condition with functional operation
• Direct replacement for worn or damaged hammer blocks
• Essential safety component preventing accidental discharge
• Ensures firing pin only contacts primer when trigger is pulled

Compatibility Note: The hammer block is interchangeable across all K Frame models, both rimfire and centerfire. This part will fit Models 10, 12, 13, 14, 15, 16, 17, 18, 19, 48, 64, 65, 66, 67, 617, and 648. The "old style" designation refers to earlier production variants.

Function: The hammer block is a critical safety mechanism that physically blocks the firing pin from moving forward unless the trigger is fully pulled to the rear. This prevents accidental discharge if the revolver is dropped or the hammer is struck. A worn or damaged hammer block can compromise the safety of the firearm.

Installation: Professional gunsmith installation required. The hammer block is an internal safety component that requires complete disassembly of the revolver. Proper fitting and function testing are essential for safe operation. This is a critical safety part - improper installation can result in dangerous malfunctions.

How to Identify Your Smith & Wesson Model: Swing out the cylinder and check behind the yoke on the frame for the model number. Model numbers began in 1957-58. If you need assistance identifying your revolver or confirming compatibility, contact us with your serial number.

Questions? Contact us at sales@usagunsandgear.com or call 770-544-8075. We specialize in Smith & Wesson pistol and revolver parts - new, used, NOS, and refurbished.