The early CVAs (round ball shooters) were known for their accuracy. 60-72 seemed to work well with 45-54s and RBs. Then the T/C line of MLers went to 48 twist in most MLers so they could shoot both Maxi balls and round balls(neither very well). Though not asked, and the originator of this thread may understand this better than I ) , I'd rule out the middle range twist rates, and choose faster rates for conicals(20-32 , I prefer fast!) and slower ( 56-76) for round balls. The 48 and +/- a few inches does neither well. I realize the Hawkin original rifles were almost all 48" twist; however, they weren't very accurate either. Just my unsolicited thoughts.