Welcome to the forum! My 10 is not free floated and I handload to find the most accurate rounds the rifle will fire. I only use IMR-4064 powder (both .308 and .30-06 for commonality) but work up different loads for various bullets. Ladder loads are part of the fun of handloading. If you plan to free float your barrel in the near future, might not be worth your time to develop loads now. Of course free float is more accurate just like your bolt action. The M&P 10 isn't a target gun but can do mighty well if reworked for it.

I switched to the small base die but am not totally sold it's really needed. It's just insurance for me as I use LC brass. However, the answer is yes for the regular die - just be sure the shoulder setback is correct. Good luck!

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