Mass, amount of fall and spring pressure are all critical for good ignition. The secret is getting that balance just right for easy bolt lift and sufficient energy to the primer. Look for .020" primer indentation, as a general rule. A little more is ok but a little less is not. This can be checked with a primed but NO powder case by gently lowering the FP down onto a primed case by holding the trigger back while lowering the bolt. Measure how far the cocking piece is inside of the bolt shroud, then repeat, except pull the trigger on a primed case as if firing a round, then measure as above. Keep muzzle pointed in safe direction at all times!