J37 Smith & Wesson J Frame Model 51 Revolver Blue .22MRF 3 1/2" Pinned Barrel ejector rod The mainspring controls hammer tension

The mainspring controls hammer tension and directly affects trigger pull weight and smoothness

Mounting: Pinned (requires pin)

military issue specification

To determine your Smith & Wesson revolver model number

J37 Smith & Wesson J Frame Model 51 Revolver Blue .22MRF 3 1/2" Pinned Barrel ejector rod The mainspring controls hammer tensionJ37 Smith & Wesson J Frame Model 51 Revolver Blue Steel . 22 MRF 3 1 2" Pinned Barrel No Locking Bolt How to determine the model number of your Smith & Wesson Revolver. Swing out the cylinder , check behind the yoke on the frame for a MODEL NUMBER. Model numbers began in 1957 58. So if there is no model number then your revolver may be older than 1957 58. In this case we can possibly still find the part you need with the serial # . If this is the case