I have a M70 .458 very much like yours that I’ve been working with for quite a few years. Light loads are fun but, at least in my mind, sort of defeat the purpose of a big bore magnum rifle, that being POWER! Getting to full power handloads can be a bit tricky because of the limited case capacity but it can be done. More than any other rifle, you need to make each shot count when range shooting. I find I can handle 6-7 full power rounds off the bench when testing or maybe 10 rounds standing. Any shooting after that is just wasted noise and ammo. And that rifle will give you a “gun headache” in fewer rounds than any other I know of. Enjoy it! You will find it a real learning experience.

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Everybody could shoot