IMR4831 has worked best for me, giving the top velocities and best groups. At least in the Three 300WSM rifles I've loaded for so far.

Using WW Brass.

165gr Bullet - IMR4831 From 60.0 grains to 68.0 grains - Winchester WLR Primer



180gr Bullet - IMR4831 From 58.3 grains to 67.0 grains - Winchester WLR Primer

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