Originally Posted by
TheTrevor
The heavier the projectile, the longer it takes for the powder charge to accelerate it for a given muzzle energy. This spreads the recoil impulse out over more time, reducing felt recoil.
In my case, shooting 40SW factory/reman ammo, I can pick between a milder 180gr load or a full-power 165gr load with a lot more snap to it. Once I switch over from accumulating brass to reloading, I'll have the option of loading even milder 180gr loads and running them with a lighter recoil spring for reliable functioning, which reportedly yields 9mm levels of recoil.