It's a variable that if someone with a tunnel was really interested, he might find some gains. Unless you're having a serious ignition problem it's probably not worth doing more than just speculating on it. Heavier springs will make more vibration, and so will a heavier pin, but it will also slow lock time. If someone finds the holy grail of firing pin weight that really makes a difference, I will just buy it. Someone else can do all the legwork in figuring it out. Bullets, powder, and primers cost too much and in some cases have limited availability for me to go spending time trying to figure it out.