Smith & Wesson Smith & Wesson K Frame Model 66 Hammer Block Old Style .357 Magnum Used - 66120B Part 66120B

Smith & Wesson K Frame Model 66 Hammer Block Old Style .357 Magnum — Used OEM Part 66120B

$6.99
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Smith & Wesson Smith & Wesson K Frame Model 66 Hammer Block Old Style .357 Magnum Used - 66120B Part 66120B
  • Smith & Wesson Smith & Wesson K Frame Model 66 Hammer Block Old Style .357 Magnum Used - 66120B Part 66120B
  • Smith & Wesson Smith & Wesson K Frame Model 66 Hammer Block Old Style .357 Magnum Used - 66120B Part 66120B
  • Smith & Wesson Smith & Wesson K Frame Model 66 Hammer Block Old Style .357 Magnum Used - 66120B Part 66120B
  • Smith & Wesson Smith & Wesson K Frame Model 66 Hammer Block Old Style .357 Magnum Used - 66120B Part 66120B
  • Smith & Wesson Smith & Wesson K Frame Model 66 Hammer Block Old Style .357 Magnum Used - 66120B Part 66120B
  • Smith & Wesson Smith & Wesson K Frame Model 66 Hammer Block Old Style .357 Magnum Used - 66120B Part 66120B
  • Smith & Wesson Smith & Wesson K Frame Model 66 Hammer Block Old Style .357 Magnum Used - 66120B Part 66120B
  • Smith & Wesson Smith & Wesson K Frame Model 66 Hammer Block Old Style .357 Magnum Used - 66120B Part 66120B
  • Smith & Wesson Smith & Wesson K Frame Model 66 Hammer Block Old Style .357 Magnum Used - 66120B Part 66120B
  • Smith & Wesson Smith & Wesson K Frame Model 66 Hammer Block Old Style .357 Magnum Used - 66120B Part 66120B
Smith & Wesson K Frame Model 66 Hammer Block Old Style .357 Magnum — Used OEM Part 66120B

Smith & Wesson K Frame Model 66 Hammer Block Old Style .357 Magnum — Used OEM Part 66120B

$6.99

Smith & Wesson K Frame Model 66 Hammer Block Old Style .357 Magnum — Used OEM Part

Genuine Smith & Wesson OEM hammer block for the K Frame Model 66 Combat Magnum revolver chambered in .357 Magnum. The Model 66 is the stainless steel version of the K Frame .357 Magnum line. The hammer block is a critical passive safety component that physically prevents the hammer from contacting the firing pin unless the trigger is fully depressed. Without a functioning hammer block, a dropped revolver or an impact to the hammer could cause an unintended discharge. This is the old-style hammer block, which fits Model 66 through 66-3. The old and new style hammer blocks are not interchangeable — verify your dash number before ordering. This used OEM part is inspected and functional, manufactured to original S&W specifications and tolerances.

Condition: Used — inspected and functional. Some fitting by a qualified gunsmith may be necessary.

Specifications

  • Part Number: 66120B
  • Manufacturer: Smith & Wesson
  • Part Type: Hammer Block
  • Style: Old Style
  • Frame: K Frame
  • Compatible Models: Model 66, 66-1, 66-2, 66-3
  • Caliber: .357 Magnum
  • Condition: Used — genuine OEM part, inspected and functional

Compatibility

Model Frame Caliber
Model 66 (original) K Frame .357 Magnum
Model 66-1 K Frame .357 Magnum
Model 66-2 K Frame .357 Magnum
Model 66-3 K Frame .357 Magnum

⚠️ Important: The old style hammer block does NOT fit Model 66-4 and later. The 66-4 introduced a new style hammer block design that is not interchangeable with this part. Always verify your dash number before ordering.

Finding Your Model Number

Swing out the cylinder and look behind the yoke on the frame. The model number and dash number are stamped together (e.g., "66-2"). Model numbers were added starting in 1957–58.

Important Notes

  • This listing is for the hammer block only. All other action parts are sold separately.
  • The hammer block is a safety-critical component. Replacement by a qualified gunsmith is strongly recommended.
  • Always function test after installation to confirm proper hammer block engagement before carrying or firing.

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