Typically LRM, but I have heard of good results with regular LR.
I would start with the LRM and see what I could get out of it. Then I might try LR if I were not happy with the results or got bored.
Changing primers, powder type, and powder weight will change POI.
No personal experience with th 7mm RM.
Get a book or three and start reading before you start stockpiling components.
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