My 1885 low wall is a .260.
You can cover all those bases very easily with one, including elk.....mine has killed two so far.

I think a 6.5cm would be the best of breed for your needs, as you described them.
7-08 would be my next choice, but recoil will increase and it won’t kill any deader....

BT53
"Where do they find young men like this?" Reporter Savidge, Iraq
Elk, it's what's for dinner....