Drop-in replacement hammer assembly for Smith & Wesson N-Frame and X-Frame revolvers. Designed to increase mass behind the hammer face, allowing a lighter mainspring tension without sacrificing ignition reliability. Replaces factory MIM hammer, sear, stirrup, and spring with machined steel components. Works with both rimfire and centerfire ammunition, though primarily used to improve primer strike consistency in centerfire loads. Maintains single-action functionality.
Compatibility
- Smith & Wesson N-Frame models: 25, 27, 29, 57, M&P R8, 325, 327, 329, 329PD, 350, 610, 625, 627, 629, 929
- Smith & Wesson X-Frame models: 500, Governor
- Requires frame-mounted firing pin (accessible only with side plate removed)
- Not compatible with K-Frame, L-Frame, or J-Frame revolvers
- Not for use with hammer-mounted firing pins
Key Features
- Increased hammer mass for reliable ignition with reduced mainspring tension
- Machined steel construction replaces factory MIM components
- Includes hammer, sear, stirrup, and spring
- Drop-in fit for current production N-Frame and X-Frame revolvers
- Manufactured in Phoenix, AZ
Install Difficulty: 2/5
Requires side plate removal, punch set, and basic revolver disassembly knowledge. No permanent modifications needed. Standard hand tools only.
FAQ
Will this work in my pre-lock N-Frame?
This component is designed for current production models with frame-mounted firing pins. Pre-lock or older N-Frames with hammer-mounted firing pins are not compatible. Verify your revolver has a frame-mounted firing pin before ordering.
Does this include the mainspring?
No. The kit includes the hammer, sear, stirrup, and spring only. You will need to supply your own mainspring and strain screw. A reduced-power mainspring is recommended to realize the full benefit of the increased hammer mass.
Can I use this with a .22 LR conversion cylinder?
Yes. The increased hammer mass improves ignition reliability with rimfire ammunition, which was the original design goal. Expect consistent primer strikes with standard velocity .22 LR loads.
Ships same business day if ordered by 2 PM ET. Covered by manufacturer warranty against defects in materials and workmanship. No returns on installed or modified components.





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