I've only taken two Elk, one Bull last season and a cow several years ago.
Both were taken with the bow. The cow with aluminum arrows and the Bull with carbon.

I don't think the type of shaft makes any difference. It is the weight of the shaft and the proper poundage of the bow along with the best and sharpest broadheads you can use.

Thsi Bull was taken with carbon arrows, Thunderhead 125 heads shot from a 65# bow.