I've taken 2 Leopards. One with the 375 H&H. The other with a Ruger #1 in 300 H&H. 300 TSX in former, 180 tipped TSX in latter. Both cats were dead under the tree. My opinion is that the 300 is the better performer on cats of this size. The leopard is not hard to kill. He is a pretty soft target and dies easily, as long as you put the bullet in the right place. A poorly placed bullet however is BAD NEWS. That being said, whatever you use, make sure you shoot it well. My choice of bullets were probably on the too hard side. Certainly for the first one.

The 257 WBY would be great on Leopard. But as others have said, you will be shooting bait as well. If using Impala, no problem. If using Zebra, you might want something a little larger. The 416 is not an ideal leopard rifle due to the velocity being a bit low. However, if you go with the 300 or 350 grain bullet in 416, that would work fine!

Have fun on your hunt. Just be prepared mentally for the hunt as cat hunting can be quite boring until (and if) he jumps into the tree. My 2nd leopard was taken this past June on the 13th morning of a 14 day hunt. At noon on day 12, we had no male cats feeding. You never know if it will happen so hang in there and enjoy the ride!

Here is a pic of the leopard from June 2011.