It also depends on another thing as well. I suspect that you have a milsurp or maybe even a sporter mauser in 8x57. If I'm wrong ignore this. The 8x57 is a great cartridge in its own right and doesn't need to prove itself any more than it already has. The 338-06, treads the same path. It is quite difficult to find a barrel maker that will make up an 8mm barrel in north america. That usually leaves you with a milsurp barrel. If you can find an 8mm barrel blank, it will cost around $400, not that price is a consideration. If your existing 8x57 has a nice bore and more importantly is repeatably acurate, it will do the job just fine on elk out to the same ranges as the 338-06, as will the 30-06 loaded with 200 grn bullets to 2500fps, just make sure the action is in good shape and handload your 8x57 to the 47000psi range it was designed for with any given bullet weight and it will perform in an exemplary manner on anything in north america. I've shot moose, elk, bear, deer and even coyotes and wolves with the 8x57 right out to 400yds, and they didn't seem to know the difference. Just learn to shoot whichever cartridge you choose under different circumstances so that there won't be to many surprises in the field and you'll do fine. That being said, go whichever way you want and find the most convenient, if you do your part tailoring the rifle and load properly, you won't have any problems with either cartridge. Your only other worry will be decent bullets, and Speer, Hornady and Nosler make some very decent bullets that hold up very well at both short and long ranges in either bullet diameter. Bearhunter