Just a quick note here. The J-Frame hit is not specified for use in Rimfire J-Frames. The product description specifically says "Works with all modern centerfire J-Frame revolvers with the frame mounted firing pin." We know the sharper tip pins will puncture a Rimfire cartridge and don't recommend our pin for that reason.
For Rimfire J-Frames I use the factory springs from a Centerfire J-frame. The springs in the Rimfire J-frame are heavier than those in the Centerfire and I've found that they tend to work very reliably.