Kbeers, it depends on what you want to do with your rifle. If, like most here, you're a committed round ball shooter, then that GM barrel is well worth the money. I've got one that delivers near MOA accuracy year-in, year-out without any fuss or bother with sight settings from year to year. Plus, the .54 RB is deadly on deer. An interesting thing that no one else mentions is that they'll shoot a 295 Gr. Power Belt bullet to the same Point-of-Aim with accuracy virtually the same as the roundball. Don't try it with heavier PB's, however; twist is too slow and the bullet won't stabilize. Basically the slow twist and deep-cut rifling the the GM RB barrel does the best job of translating its twist to spin on a roundball.
OTOH, if you plan to hunt with heavy conicals, the longer bullets will require a faster twist and the conicals will seal the bore better with shallow rifling. 1-in-48 works well with conicals, but faster twists such as 1:38, 1:32, etc. might do even better. Most of the fast twist barrels have shallow (or shallower) rifling demanded by conicals, though I've heard the Trade Rifle barrels are cut deeper than most.
A 1:48 twist will also allow you to shoot roundballs very accurately at reduced loadings. This makes for a great plinking, target shooting and pest load. But the fast twist barrels with their shallow rifling aren't known for best roundball accuracy at full power loadings. I think this is as much due to the depth of rifling as the twist rate. At full power velocities, fast, shallow rifling does a relatively poor job of translating its twist through the patch to the ball.
Sorry this is so long. Just felt like writing today.
Bob
