There are dozens of right answers to this one. I take it that, this is just a theoretical, kick it around question.
For the person who already has one rifle, the question is what to buy for back-up and perhaps other use.
If the question is: What should the person with no deer level rifles buy, that is different.
In my case, I would take my 338 for the elk, with my 06 for back-up. If the "wrong" animal came along first (assuming I could hunt either; maybe change ammo. When I went for deer only, I took my 444 Marlin with the 06 for back-up. Obviously, at limited woods ranges, either will work.
My selection would be determined by probable distance. My ammo selection would be a premium bullet for the elk.
If I were buying 2 rifles, I would either buy a 280 or an 06 for one as they have the widest bullet selections and similar ballistics. Depending on likely distance, the back up could be a "brush" caliber if less than 200 yards. If more is assumed, I would try to select something which, could take either animal but, might fill another role; that would depend on your other hunting. For an eastern hunter, the "brush" caliber such as a 444 Marlin, 45-70, 450 Marlin Magnum might be my choice. They would work well for bear too.
In my mind, you MUST have a back up. Who wants to be miles from anywhere on a long awaited hunt when a rifle is dropped or a scope gives up.
Last edited by Big Bullets; 11-02-2011 at 07:08 AM.