Rifle primers in 357 magnum.

A test for a Smith and Wesson revolver, model 28, 357 mag., may work on other guns also<> Gun empty.
Dry fire gun and hold trigger fully to rear.
Cock hammer with thumb.
Hook a weight around the hammer (for example 3 1/2 LB minimum weight for 357).
The hammer must not move rearward when the gun is lifted.
The hammer should lift 3 1/2 lbs without going into the cocked position.