While doing your research it may be helpful to read some of Finn Aagaard's writings on the 7x64. It was his primary "light" rifle choice for many years as a PH and he held the cartridge in high regard. He took many leopards, and all the plains game species with it. As did many other hunters, but Finn wrote about it. You won't need a bullet heaver than 175-176 grains for hoofed game. And if I was using a 7x64 for leopard, I'd choose a faster 160 gr Nosler partition or RWS H-mantel or similar quick opening bullet that has a rear portion that hangs together to penetrate deeply. It is my understanding that leopards are particularly susceptible to shock from a fast bullet, and so faster ( within reason) is more suitable than heavier bullets for them. Someone with real experience and not book learning please correct my presumption if that is not correct. For what it's worth, I took the heaviest elk I've ever shot (bigger than a typical Oryx or Kudu I suppose) with a 7x64 and 160 gr. RWS Ideal Classic bullet.