I too went with the mil spec 5r 26" 300 wm, after a bunch of reading on this site. Reading through this thread makes me feel even more confident that I made the right choice. I couldn't go full high dollar custom, but instead did my homework on the best factory rifles.
I too am going to leave it in the factory configuration for break-in and initial load development starting with 200 grain ELDX and H1000. I'll re-assess later if I need any improvements, which will be small first, such as bedding then a trigger. I'll have a few good range sessions before I decide if I need to brake it or not, I do have a JP recoil eliminator if need be.