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S&W J Frame Concealed Hammer MIM New Style .357 Mag Used, Part 340107

Sale price  $29.99 Regular price  $37.99

Factory OEM Smith & Wesson concealed hammer (Centennial style) for J Frame centerfire revolvers. MIM (Metal Injection Molded) construction, new-style design. Used surplus part in good working condition.

Specifications

  • Part Number: 340107
  • Hammer Style: Concealed (Centennial)
  • Construction: MIM (Metal Injection Molded)
  • Style: New Style
  • Caliber: .357 Magnum / .38 Special (centerfire)
  • Frame Size: J Frame
  • Condition: Used / Surplus
  • Brand: Smith & Wesson

Function

The concealed hammer (also called an internal or shrouded hammer) is fully enclosed within the frame, eliminating external hammer snag points for smooth draw from a pocket or holster. It strikes the firing pin to initiate ignition. The new-style MIM construction delivers factory-spec geometry and consistent ignition. A worn or broken hammer will cause misfires or failure to fire.

Compatibility

Model Caliber Frame Notes
Model 340PD .357 Mag / .38 Spl J Frame AirLite Sc — Centennial, new style
Model 360 .357 Mag / .38 Spl J Frame Centennial — verify new style
Model 40 .38 Special J Frame Centennial — verify new style
Model 42 .38 Special J Frame Centennial — verify new style
Model 442 .38 Special J Frame Centennial — verify new style
Model 640 .357 Mag / .38 Spl J Frame Centennial — verify new style
Model 642 .38 Special J Frame Centennial — verify new style

Important: This is a concealed hammer — only fits Centennial-style J Frame revolvers. Not compatible with exposed hammer models (36, 37, 60, 649) or rimfire J Frame models (43, 63, 317).

Installation Note

Professional installation by a qualified gunsmith is recommended. Verify hammer-to-firing-pin alignment and function-test before returning to service.

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