I've used the 300WSM - ballistically identical to the 300 H&H - with 180 grain Partitions on eland. I believe a medium - 375, 416, 404 - would be a better choice on lion. If the angle is not ideal or follow ups are needed to stop a wounded animal, the mediums would offer greater power.

Is life so dear, or peace so sweet, as to be purchased at the price of chains and slavery? Forbid it Almighty God! I know not what course others may take, but as for me, give me liberty of give me death! P. Henry

Deus vult!

Rhodesians all now