I shoot a 1:24 twist Investarms Hawken Hunter Carbine as sold by Cabelas. It's got a 20" barrel, modern adjustable sights, a recoil pad, montecarlo stock, blacked out furniture, a hawken for the modern hunter. It likes 240 grain .44 cal sabots, but for lead, and I kinda prefer 'em, it shoots a 385 grain Hornady Great Plains minie quite well. I don't elk hunt with it, in fact, I haven't hunted with it at all in all these years. It's just a pain to have to load up for a hunt when I can grab my Contender and just drop in a .30-30.
But, I expect that minie would work on an elk. Only thing I've ever killed with it is paper.
I say shoot what's accurate and legal. If that's round ball, so be it.
I also cast a 360 grain Lee improved minie which shoots quite well. Need pure lead, not range scrap, though. If the lead is too hard, minies won't work as designed.
Rifle twist rate has a lot to do with what your gun will shoot. You'll just have to experiment. There is no substitute for range time and practice.