Smith & Wesson Model 51 J Frame Hammer Block .22 Magnum, Part# 51120
$6.99
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Smith & Wesson Model 51 J Frame Hammer Block .22 Magnum, Part# 51120
$6.99
Smith & Wesson Model 51 Hammer Block – Part# 51120
This is a genuine factory Smith & Wesson hammer block for the J Frame Model 51 revolver chambered in .22 Magnum Rimfire (.22 WMR). An old-style used part in serviceable condition. The hammer block is a critical passive safety component — it prevents the hammer from contacting the firing pin unless the trigger is fully depressed, protecting against accidental discharge from drops or impacts.
If your revolver has a worn, cracked, or missing hammer block, replace it immediately before returning the firearm to service.
Part Details
- Part Number: 51120
- Part Name: Hammer Block
- Condition: Used, factory original (old style)
- Frame: J Frame
- Caliber: .22 Magnum Rimfire (.22 WMR / .22 M.R.F.)
- Function: Passive drop safety — blocks hammer-to-firing-pin contact unless trigger is fully pulled
Model Compatibility
| Model | Caliber | Frame | Compatible |
|---|---|---|---|
| Model 51 | .22 Magnum (.22 WMR) | J Frame | ✅ Yes |
| Model 53 | .22 Jet / .22 LR | J Frame | ⚠️ Verify fitment |
| Model 63 | .22 LR (rimfire) | J Frame | ⚠️ Verify fitment — different rimfire caliber |
| Model 34 | .22 LR (rimfire) | J Frame | ⚠️ Verify fitment — different rimfire caliber |
| Model 36 / 60 | .38 Special / .357 Mag | J Frame | ⚠️ Verify fitment — centerfire |
| K / L / N Frame | Various | Larger frames | ❌ Different frame size |
Note: The Model 51 is chambered in .22 Magnum Rimfire (.22 WMR) — not .22 LR. Hammer blocks are frame-specific and not interchangeable between J, K, L, or N Frame revolvers. Parts may also vary between rimfire caliber configurations (.22 WMR vs .22 LR) and between old-style and current-production revolvers. Always confirm your exact model before ordering. Model numbers are stamped on the frame behind the yoke when the cylinder is swung out.
Installation
Hammer block replacement requires full disassembly of the lock work. As a critical safety component, we strongly recommend installation by a qualified gunsmith. Do not return the firearm to service without verifying correct function after installation.
Questions about fitment? Call or email us — we're happy to help.