I like my .300wsm out here on the prarie, I also use a 7wby mag with 154gr bullets it works well too. A 7 stw might fit the bill for ya, with a bit of kool factor. I just picked up a 8 rem mag, little big for deer maybe, but it should work pretty good out here. Any magnum should really shoot flat enough for you if you have a range finder. .325 wsm would be a good one too, I guess it depends on how much recoil you want to deal with.