I had a custom 7x57 built. Sold it when the knee went bad.

Lovely cartridge. Easy to shoot well due to its lack of recoil. Perfect for Red Deer and game up to 100kg.

It has had a lot of press and I'm still not convinced ( based on my own experience ) it is as capable on larger game as some believe.

For a traditional four gun battery to hunt the world I would put it here:
.220 Swift, 7x57, 9.3x62 then .416 Rigby.

I'd feel a more versatile line up would be:
.243W, .300 mag, 9.3/375H&H and .400+