There is a big mis-conception about 1-48 twist barrels in .50 caliber. There is no problem getting excellent accuracy with them. It's a great twist. The barrels will shoot heavy conicals with acceptable accuracy and excellent accuracy with patched roundballs. Here is a typical 3 shot group with open sights off the bench at 50 yards. If I had 40 year old eyes instead of 71 year old eyes the groups would be tighter I'm sure.
.50 Caliber CVA St Louis Hawken 1-48 twist. From the bench @ 50 yards.