S&W J Frame Firing Pin Assembly with Spring & Retaining Pin New Style .357 Mag Used, Part 340181
Factory OEM Smith & Wesson firing pin assembly for J Frame centerfire revolvers, new-style design. Includes firing pin, firing pin spring, and retaining pin. Used surplus parts in good working condition.
Specifications
- Part Number: 340181
- Includes: Firing pin, firing pin spring, retaining pin
- Style: New Style
- Caliber: .357 Magnum / .38 Special (centerfire)
- Frame Size: J Frame
- Condition: Used / Surplus
- Brand: Smith & Wesson
Function
The firing pin assembly transfers hammer energy to the cartridge primer to initiate ignition. The firing pin spring controls forward travel and returns the pin to the rest position after each shot. The retaining pin secures the assembly within the frame. A worn, broken, or missing firing pin or spring will cause misfires or light strikes. Replace with this complete factory assembly to restore reliable ignition.
Compatibility
| Model | Caliber | Frame | Notes |
|---|---|---|---|
| Model 340 | .357 Mag / .38 Spl | J Frame | New style — verify before ordering |
| Model 340PD | .357 Mag / .38 Spl | J Frame | AirLite Sc — New style |
| Model 360 | .357 Mag / .38 Spl | J Frame | New style — verify before ordering |
| Model 360PD | .357 Mag / .38 Spl | J Frame | New style — verify before ordering |
| Model 640 | .357 Mag / .38 Spl | J Frame | New style — verify before ordering |
| Model 649 | .357 Mag / .38 Spl | J Frame | New style — verify before ordering |
Important: This is a new-style firing pin assembly. Verify your revolver uses the new-style design before ordering. Rimfire J Frame models (43, 63, 317) are not compatible — centerfire only.
Installation Note
Professional installation by a qualified gunsmith is recommended. Verify proper headspace and function-test for reliable ignition before returning to service.