Jim..........we start to make a barrel using round stock. We first drill the proper size hole, for a given calibre, then place
the blank in our lathe, on centers, and turn the whole blank concentric with the bore. At this time we also remove metal
in somewhat a "swamped" configuration........no tapers, but is stepped down in size to the small part and then back up
to the flair at the muzzle, in accordance with drawings that we make for each style of barrel. The barrel is turned to where it is about .125 bigger than the finished octagon size, so we are basically milling only about .063 off of each flat.
The blank is locked into a tracer mill and is milled one flat at a time. We always spin the barrel 180 degrees after each
flat is milled, and make sure it returns to the same position, by usiing a dial indicator, to eliminate the problem of warping.
Takes about 2 hours to mill a 42"barrel. After milling, the bore is reamed up to proper size, then rifled. When we first
started in the barrel business we were taught to drill, ream, and rifles the blank first, however, we found that when you
do it this way, and by the time you have turned and milled the outside shape to the barrel, many times it would relieve
stresses in the steel and you would end up with a bore that looked like it had reamr rings from one end to the other.
Oh, the joys of learning......costly too...........Don