if you go w 160 go easy, keep pressures low. again look for that sweet spot verses velocity. Problem I had in 1988 with a muley and a Rem 700 280 was energy at 465 yards- not nearly enough. After that hunt I went to a 280 AI follwed by a 7mm STW. I got the deer but it took 5 hits across an alphalfa field. 700 Rem which meant i had to reload. I was shooting factory 140 corelocks. keep'em closer than that. I am not a big elk or muledeer hunter, but I would say 250 yards on elk and 350 yards on MD for energy with a 280. Maybe someone will add to this on your energy. Good luck. JHG