As someone mentioned, when loading Barnes projectiles you might find that they need a little "jump" before the rifling for best accuracy.
It might be as big as a 50 thousands jump or as small as a 20 thousands.
Your 4064 might work in sine 300WSM loads, but the 4198 won't work. The best powders I have found are RL15, W760, H4350, IMR4350, IMR4895, and Varget. By "best" I mean will produce great velocity and are accurate.
Good Luck!
