Why not one of the 6mmbr or variants like the 6XC?
I have a 6br with 75g VMAX runs around 3300fps with a very good squirrel splat factor. The accuracy in absolutely incredible. We have shot squirrel heads consistently at 300 yards. Teach them to stick their head out. If you want to shoot under 600 yards it is pretty hard to beat.
Or do you just like the big flame.
Barrel life is almost forever compared to the calibers you mentioned.
How about the 25 WSSM with 75 grain bullets at 3800 FPS?
Seriously why not the 6mmbr.