What caliber is your friends rifle that you are borrowing? Have you killed elk with it? Any reason not to stay with that caliber? Also, you are in Wyoming and should hunt antelope too.Id suggest a 6.5 PRC, 270, or 30-06. If you were just hunting elk and nothing else I’d suggest a 300 win mag, 30 nosler, 300 prc as good all around choices. If you wanted multiple guns I’m currently using a 338 Lapua for my longer range elk rifle and a 325 wsm as my packable elk rifle. Like someone already said, there are lots of good choices for elk. A 28 Nosler is also a great cartridge and would be a very good choice for an all around gun in Wyoming