Years ago I would have said 7mm Rm or a 7mmSTW.
But now If I could have only one rifle that would/could do everything Out to and past 1000 yards
It would be a 300 RUM.
It can be loaded down to 30/06 velocities with a 150 grain bullet for 3100 ft/sec to 3550 ft/sec
and a 200 grain bullet from 2670ft/sec to 3025 ft/sec.
With all of its versatility it will do just about everything at 100 to 1000+yards on any North American game or target.
There are many different and capable cartridges that could do most things needed but the 300 RUM
would be my choice now days. The only other cartridge would that I would consider would start with a 338 xxx
J E CUSTOM
I have a good one for sale on here right now.