Question for the OP---Have you ever hunted or shot an elk with anything before? If you haven't, a big bull takes one heck of a poke and conventional wisdom says to hit him with close to 1500ft/lbs of energy at POI for good penetration with the correct bullet to obtain a humane kill.
Take a look at Parker bullets. I use the 250 Jacketed Ballistic Extremes in my Encore. They shoot .75" at 100 yards and shoot well in some of my buddies omega rifles. Longest shoot to date was 172 yards on a whitetail buck. I plan on trying some Parker's 275s.