As to get a M1A in 30-06, I do not Believe There's been 1 produced just before. Nonetheless, the M1 Garand went through some experimentation immediately after WWII (and I think even a little bit throughout the war) to include a removable mag, which was The idea with the M14. https://30-06-garand-ammo-differe55295.blogdemls.com/19674772/a-review-of-federal-30-06-for-m1-garand-near-me