A PRB always shot really good from my old Renegade .54. Later i went to a GM 1-70 barrel, and really didn't see a huge difference in accuracy.

The GM did show better accuracy if I use a heavy charge of powder. If I stayed around 80gr it was too close to call. The GM was better at offhand shooting though, because of the added weight.

Overall, the TC barrel was pretty damn accurate with a PRB.