At 15 yards, a 300 gr Partition from a 375 handload @ 2475 f/s (between the front legs at the base of the mane) knocked an adult male lion down seemingly with authority. But, he got right back up and crawled another 20 yards or so away from us. I kept shooting 'til the mag was dry, but the additional 3 rounds were likely unnecessary. A sample of one.
But having that experience, and having used a 416 Rigby on other large game, I'd be inclined to go with the 416, provided the shooter can handle it. 416 level recoil is a significant step up from a 375, IMHO.
IIRC, Harry Selby thought the Rigby was the ultimate cartridge for lion, in his considerable experience. Hard to beat that kind of recommendation.
Pete
