I've been fortunate enough to have been on seven guided hunts for elk/deer, in four states of the West; Idaho, Colo., Wyom., and Mont. I've seen quite a variety of guns used by the outfitters, the guides, the wranglers, and the cooks (yep, you'd better believe the cooks keep guns in the cook tents!)
Generally, I've seen more .30-06s, .308s, and .270s. A few .300 Mag and 7mm Mags. I hunted with an outfitter in Colo., who'd carried a Savage 99 in .243 for many years, and he always got an elk after the dudes went home.
The handguns were mainly .44 Mags and .41 Mags. A few .357s and a couple of .45 L.C. with heavy loads. The handguns were always packed around camp in griz country, which was in Wyom., and Idaho.
In northern Idaho, I hunted with an outfitter who had a young woman who was his supplies and meat packer, and she carried a Ruger Security Six .357 in a shoulder holster and a Marlin .30-30 in a saddle scabbard.
My guide on the hunt in Idaho carried a lightweight Rem. 650(?) in .350 Rem. Mag., and a .357 Mag in a shoulder holster.
Mainly, the guns were fairly eclectic.
FWIW. J.B.