Update:

Due to the overwelming advice that I get heavy with my 300,
I loaded a bunch of Barnes 180 XBT with varying amounts of IMR4350. I chronographed them to find something worth working with further.

I decided upon 70.3 gr of IMR4350 with an average velocity of 2943. Wasn' t the fastest load but with a spread in velocity of only 12 fps, I figured it had the best chance for accuracy.

Popped a few rounds into a target at 100 yards. Seemed to hover around 1 inch. I have a Que Muzzle Brake on my 300 (adjustable like a BOSS) and will do some more tweaking. If it turns out to be as accurate as it is consistant, I will forgo the 150 Nosler Partitions and take the 180 Barnes XBT as elk medicine instead.

Figures show ME of 3305 for the Noslers and 3462 for the Barnes.