I think Rice uses a Planer to take the metal off. We used a milling machine. I don't know that one method is better than the other. Someone made the statement that the change at the end of the small part, where it flaired at the muzzle was abrupt, but you got a second one and it was slightly better. While I have never seen their machine, I think
the cutter basically follows a pattern that they have in a fixture on the mill. If they have a pattern in the mill to do lets's
say for the 38" series of barrels, all of the different weights of barrels in this series would have the same profile on the outside, they would merely raise that planer cutter to make the larger series of barrels, or lower it make the A and B series of barrels....simple. Now get out that file and draw file it, shouldn't take more than a half hour........Don