I had a factory 454 barrel that had been rechambered to 460 by David White. I never did get that barrel to shoot well. I ended up trading it off because it was just frustrating.
Something to consider with your loads, are they handloads or factory? If they're handloads, be sure that the bullets you're using are rated for the velocities that you get from the 460. I actually had bullets come apart because they were getting pushed too fast (this was mostly intentional

) Also, I don't know what difference it would actually make, but Smith&Wesson revolvers in this caliber use a gain twist rifling. I believe that this was to help the bullet gradually increase it's RPMs and reduce bullet failures.
As for TC barrels in general, they seem to be hit or miss. I've had a few that were amazing shooters. But I've also had a couple of real disappointers. Good luck!
Andrew