Apples and Oranges ..... with Apples being PRB rifling vs. Oranges being rifling more suited for lead bullets of the Minie/Burton or Prichartt type.
The rifling depth, around .010 +/-, on Hawken type rifles (Apples) is different than the depth of the musket 'type' rifling, which are around .005 +/-.
As for my information regarding 1:48 HAWKEN barrels? Spent a couple of weeks with an Army buddy messing around with this father's rifle (CVA I think?) back in the early '90s trying to get it to shoot any decent groups - best was around 8-9 inches at 100 yards. We changed out balls (.490 and .495), different patch lubes (store bought and home made), powder loads of 50gr up to 100gr, and pillow ticking (.010 to .022) with disappointing, and frustrating results. Since that time I have shot many matches as well as informal range sessions with other shooters with 1:48 barreled Hawken / Plains type rifles and the results with those guns were all usually poor with a couple that were marginal at best. Almost every one of them that I let shoot my 2012 purchased GPR with 1:60 twist caused them to either purchase a GPR, sell or retire their 1:48 guns, or purchase replacement barrels with PRB barrels for said guns.
Brazosland, you got yours to work and I am happy for you. It's just that the general consensus, and my own experience, is that 1:48 barrels deliver marginal at best but piss-poor in general accuracy. I like accuracy, but more importantly, I have too much respect for game animals to shoot at them with hardware that produces marginal accuracy. Yes, the original Hawken / Plains type rifles were 1:48, but if these barrels were such great shooters, why are / were there so many other models produced with PRB twist barrels out there? Why did Lyman, through InvestArm, offer a 1:60 twist barrel (just to name an example)? On a similar note, why the hell did Lyman let Pedersoli change the .50 caliber on the new Great Plains Signature rifle to 1:48? Big, huge, mistake.