With all this 35 love going around, I'd be remiss if I didn't mention the grand daddy of them all, the 350 Rigby Magnum

[Linked Image]

Belted magnum performance without the belt, and feeds slicker than snot with it's gradually tapered case.

Downsides would be ammo availability, brass availability and load data being scarce. But it'll handily push a 250 gr bullet to 2700 fps with 66 gr of RL15 or 71 gr of H-4350 and the one I had made would group under an inch.