Elk are not hard to kill. It’s fairly easy to hit a target that size (32 inches back to brisket) at 300-400 yards with a 140-165 grain class bullet. The key really is a light compact rifle to reduce fatigue from the riggers of hiking through deadfall timber at altitudes of 10K feet all day and resume the next. After that the last thing you need to worry about is shooting a hard kicking 30+/- ft-lbs recoil magnum to make a typically less than 200 yard shot in dark timber on a target that size. The 500+ yard shots on elk with magnums is mostly fairytales, although some seasoned rifleman do it on occasion. An elk is no match for a 308 Win with 165 NPT. Your apprentice will find it more uncomfortable to achieve enough confidence in taking any shot on his first elk, especially if that shot exceeds 300 yards, then top that off with around 30+/- ft-lbs of recoil and you sow the seeds of doubt. Doubt is the worse thing the human psyche can posses when looking for success. Only one man’s opinion.