Originally Posted by James K
Here is the problem. In order to fire a primer, the firing pin needs a certain amount of momentum, which is velocity x mass. The hammer on a J frame revolver already has low mass (compared to say, the hammer on an SAA Colt), so it needs velocity to fire reliably. That comes from the spring. If you weaken the spring too much, the gun may not fire or may fire under ideal conditions but fail if cold or dirty. I don't say not to reduce the spring tension, but agree that testing is absolutely necessary and building muscle strength is also a good idea.
The primer is ignited by the power
delivered by the firing pin, not momentum. Think of a swinging hammer (high power/low momentum) and a very slow-moving tractor (low power/high momentum) acting on your car's bumper. Chances are, the hammer will dent it, whereas the semi will simply push the entire car with little damage to the bumper.
All else equal, a lighter hammer picks up speed and delivers more power. One can therefore reduce spring tension a bit without losing reliability with a lighter hammer. But...as mentioned, power from a lighter hammer is more easily robbed if the action isn't true and smooth.
At any rate, the main issue with J-frames isn't the weight of the hammer (bobbed or not), but less leverage: Springs are stiffer to deliver sufficient oompf from a shorter hammer, and the smaller trigger has less mechanical advantage available to retract the hammer. It's a double whammy that makes for a stiff pull.
To the OP, there are numerous spring kits for the J-frame, but Apex Tactical's generally get very good reviews, and they do offer a J-frame kit
. I'd also suggest a gunsmith to smooth the action.