Originally Posted by
bronko22000
I was thinking the 1:66 twist because its close to the Pedersoli (1:65) & GM (1:70), and same as Lyman GPR.
Bob Hoyt can put any twist in it and recommended the 1:60 for the .54. I did a couple searches for the optimum twist rate for shooting PRBs in a .54 but couldn't find a solid answer. If I go this route I may just take the expert's advice and go with the 1:60 unless someone can prove to me the 66 is better. Keep the comments coming.
GPR is 1-60.
Just to add more confusion. The original Hawken was a deep groove 1-48 twist. It was made for the PRB.
I talked to GM a few years ago, and he told me they spent a lot of time coming up with the 1-70 twist as being ideal for a PRB. I believe it was used in all calibers.
So, is there a set answer? I don't think so, but all PRB barrels have one thing in common. They have deep rifling.