You guys are running scared. Std vel 150gr ammo isn't going to damage the M1. Std pressure 06 loads are manuf w/ plder rifles in mind, hence lower pressures. High vel stuff, using slower powders or heavier bullet loads like 180gr, are where the op rod gets banged up. JMO, I would shoot a std vel 150gr load & not worry over it.
"Given adequate penetration, a larger diameter bullet will have an edge in wounding effectiveness. It will damage a blood vessel the smaller projectile barely misses. The larger permanent cavity may lead to faster blood loss. Although such an edge clearly exists, its significance cannot be quantified".