Helped a buddy with his Browning AB3 300 Winny. I assumed that he'd need some 4831 or 7828 burn rate type powder for his 180 NBTs. Nope, IMR4350. 3000-ish and really accurate.
IMR4350 is and has always been the first powder I try in my new 300wm rifles. Load up near max with a good 180 and it's usually golden... Back when I only owned 1 rifle, it was a 300wm. I settled on the 200gr partition for both deer and elk. Its pretty hard to beat that combo. I tried Accubonds, when they first came out, but they were damned finicky, so I went back to partitions. Great bullet you know you can depend on. OP, you might also want to develop your loads closer to hunting season. I've had some RL22 produce some pretty sporadic results, depending on temperatures. You are also right to look at all of your groups. Superimposing the 3 3 shot groups on to one target for a better reference is smart. The composite of the 9 shots tells a better story. A lot of guys here will shoot 3 shot groups, pick their best one and post it here, thinking their gun is sub half moa, when in all reality it may only be a good 1.5 moa rifle. This is one reason I shoot 10 shot groups, it gives you a better idea of your rifles true accuracy, and precision along with true POI vs. POA.
