Well, opinions you will get, so here is mine (and take it for what its worth since Im no "expert :wink: :lol: .)
I think you are on the right track with sticking to the sub-bore (less than .30 cal.) These smaller calibers have a reputation of being lighter in recoil with the more higher ones (like the 6 and 6.5 bores) still holding great B.C. bullets. I dont know what kind of "recoil" experience you have, but Ill assume you are like the average person (me included) "the less recoil the better." I think the .270 is a good choice, and depending on distances involved still holds its weight for elk. Another great round to look at is the 6.5x55 Swede. The Swedes have used for eveything from; War, match and some benchrest shooting, and taking down moose. The 6.5 has a reputation of being accurate and good game stopping power. Guns maybe a bit harder to find for this caliber though.
And of course there is still old standbys like the .280, 25-06 (which is probably too light for elk, but not Pronghorn).......and heck, lets not forget the .30-06 (which would basically give you a choice of ANY gun make you could possibly want.)
Brian