You will have a very interesting Summer.
I handload so I have not much to contribute. My 280 is in love with the 140 grain weight.......My 300 model 70 likes 150's and the A-Bolt likes anything, its got the BOSS. I only stick 180's in the mag but it does 125's pretty good.
Buddy of mine has a young son shoots a 7 with reduced loads. Not because the kid can't handle the recoil but because dead being dead, the lower velocity does the deed.
A 300 with say a 180 or heavier would be pushing around 2500 FPS in factory stuff and that will roll them over from 300 in no problem.