Originally Posted by Edd
Do you have any pressure data on this?
None except that replacing a weak firing pin spring with a new/strong one makes bullets shoot out faster. And with more uniform velocity. Top long range competitors have known this for decades.
Made some tests years ago with a Win. 70 spring that had dropped to 20 pounds of force from the factory standard of 23 pounds; 'twas cut off to drop the force to about 16 or so pounds which was just enough to consistantly fire the primer. Bullets dropped about 2 or 3 more MOA at 1000 yards and vertical stringing went from about 4 inches with a 26 pound spring to about 25 inches with the weak one. This was years ago and I'm remembering as best I can, but weak springs do cause lower bullet velocity and higher velocity spreads. But if muzzle velocity drops and spreads for the same load on the same day with the same ammo as it shot great with a heavier spring, that's proof to me the peak pressure followed the velocity direction and spread.