For most, I'm guessing, it has to do with the stiffness of the recoil spring. I know that the first models of the Colt Woodsman pistols function best with standard velocity ammo, and that the hammering from high-speed will eventually cause undue wear.
A stiffer spring would likely alleviate the problem--but the downside could be that the rifle wouldn't cycle properly with standard speed ammo.
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