I think you basically HAVE a 45-70 barrel on there now (except someone turned it to junk). Muzzleloaders and centerfires are different in that centerfire calibers are generally stated in groove to groove measure and muzzleloaders can be anything close to a specified caliber - but generally based upon a land to land measurement. Whites basically use those same centerfire barrels yet quote land to land measurement. A .45-70 barrel having a groove to groove of .458 and a rifling depth of .0035 would have a land to land of... .451

It's my belief that Doc first used barrels that were truly intended for centerfire use and that is how we wound up with some rather odd sounding calibers in the Whites. They really aren't odd at all.

But I don'teven suspectwhut da heck Gonic did.