I agree with jwp475, If you know what you can do, and aren't "pushing the limits" (i.e. being an irresponsible hunter) you could take an elk with that calibre and a very good bullet - however the qustion he asks is telling too - he isn't sure and that tells me he either needs to get confident or choose a different weapon. I would say he should prepare for both and get some range time in along with researching bullets AND possibly look at a second weapon if the other two don't boost his confidence - and that doesn' mean blind arrogance either.
Either way, Im glad he asked instead of assuming he could take any animal with any calibre.