RE: Best Elk Cartridge for hunting in Montana or Colorado?
I wouldn't skimp on ammo for elk. Affordable often means cheaper, softer bullets; not the best recipe for elk. And the .308, 30-06, or .338 would be my pick. Savage makes a great affordable rifle, but finding a scope to fit their long action is kind of a pain. A Bushnell Elite 3200 or 4200 in 3-9x40 should fit with the right mounts. And keep in mind that aStevens 200 is a Savage without the Accutrigger. My Stevens .243 shoots less than an inch at 100 yards with several loads, and only cost me $259.
Your question is really pretty vague. More info could lead to better responses. Would you use the rifle to hunt anything else besides elk? Do you live in Montana? If not, then where? What do you hunt currently? What kind of hunting ranges do you anticipate? Do you currently own any rifles? If not, what's your experience level with them? Anything else you want to throw in could possibly help...
If you were just asking out of curiousity, then there's only one answer;and that is that there is no simple answer. The worldis just too dynamic with too many variables. Which caliber for what is just one of many questions that people argue about and will continue arguing about forever. It's fun to talk about, but there's really no clear right/wrong answer in the end.
For example: If you hunt thick timber and don't anticipate shooting beyond 150 yards or so, then I'd recommend a lever action 30-30 or 45/70. Marlin makes a pretty affordable model. If, however, you hunt in really open country with long shots, then a .300or big .338 magnum would probably be the way to go. I just recommended the .308, '06, and .338 because they're all pretty versatile and common. A wide selection of ammo should be fairly easy to find.