Smith & Wesson Revolver K Frame Model 10 .38 Special ctg. Hammer Block on a white background with a label.

Smith & Wesson K Frame Hammer Block Old Style - 10120D

$5.99
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Smith & Wesson Revolver K Frame Model 10 .38 Special ctg. Hammer Block on a white background with a label.
  • Smith & Wesson Revolver K Frame Model 10 .38 Special ctg. Hammer Block on a white background with a label.
  • Smith & Wesson revolver part on a white background with a label
  • Black metal key-shaped object on a white background
  • Smith & Wesson Revolver K Frame Model 10 .38 Special ctg. Hammer Block on a white background with a label.
  • Smith & Wesson revolver part on a white background with a label
  • Black metal key-shaped object on a white background
Smith & Wesson K Frame Hammer Block Old Style - 10120D

Smith & Wesson K Frame Hammer Block Old Style - 10120D

$5.99

Smith & Wesson K Frame Hammer Block – Old Style

This factory original Smith & Wesson K Frame Hammer Block (also called the safety block) is a critical passive drop safety component that sits between the hammer and firing pin. When the trigger is not fully pulled, the hammer block prevents the hammer from contacting the firing pin — even if the revolver is dropped or the hammer is struck. Only when the trigger is fully depressed does the block lower, allowing the hammer to fire the cartridge. A missing or damaged hammer block eliminates this drop safety protection and must be replaced immediately.

Part Details

  • Part Number: 10120D
  • Manufacturer: Smith & Wesson
  • Frame: K Frame (Medium Frame)
  • Style: Old Style
  • Function: Passive Drop Safety / Hammer Block
  • Condition: Used – Factory Original, Functional

Model Compatibility

Model Caliber Type Compatible
10, 10-10, 12 .38 Special Centerfire ✓ Yes
13 .357 Magnum Centerfire ✓ Yes
14, 15 .38 Special Centerfire ✓ Yes
16 .32 Long Centerfire ✓ Yes
17, K22 .22 LR Rimfire ✓ Yes
18 .22 LR Rimfire ✓ Yes
19 .357 Magnum Centerfire ✓ Yes
48 .22 Magnum Rimfire ✓ Yes
64 .38 Special Centerfire ✓ Yes
65 .357 Magnum Centerfire ✓ Yes
66 .357 Magnum Centerfire ✓ Yes
67 .38 Special Centerfire ✓ Yes
617 .22 LR Rimfire ✓ Yes
648 .22 Magnum Rimfire ✓ Yes
L Frame models Various Various ✗ Not Compatible – Different hammer block

⚠️ This is the old style K Frame hammer block. The hammer block is interchangeable across centerfire and rimfire K Frame models — not caliber-specific. This is a safety-critical component — professional installation and full drop safety function testing by a qualified gunsmith is required before returning the firearm to service.

Installation Note

Hammer block replacement requires side plate removal and action disassembly. Professional gunsmith installation is strongly recommended. Always perform a complete drop safety function test after installation.

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