You can get a 1917 Remington Enfield action pretty reasonable, A stock from Boyds, and a barrel in any of the calibers you mentioned. Good, strong action.
I made a 416 Rigby and a 340 Wheatherby one that action. You could put one together a lot cheaper then buying one.
CPT USAR Ret
USAMU Sniper School Oct '78
Distinguished Rifle Badge 1071