Micah / Richard,
I use wooden shims to align the barrel height and side to side. I then use a wooden wedge on the top of the barrel to lock it into place. I think I have a better picture of the barrel locked into place.
TMerkley,
The cutting bit is made from a piece of 8" smooth file. I made one using the existing file teeth on the edge of the file, adjusting the width with a disc sander and stone and I made a second cutter from the same file only I cut in teeth that scrape the groove on both strokes. It is a copy of the cutter they use on the rifling machine at Dixon's.
Any other questions or request just let me know. I will try to be a little more expedient in posting answers.
Dave