Scott, I have personally pulled both broaches and buttons and made my own barrels in someone else's shop. I know how those barrels are produced.

The hammer-forging is a different story. I have seen video of it, and the reason I said "tube" is that the operator grabbed a "tube" out of a bin and slid it over the mandrel. This "tube was, just judging from the video, about 1-1/2" in diameter and only about 14" long with a hole that looked to be about 3/4" in diameter. The operator pushed the button and in seconds the barrel was profiled and had it's rifling. I don't know what I could call it but a "tube" It looked like a real thick-walled pipe.

I also saw a video of barrels being made for Uzi. The "tubes" they were using were much shorter, perhaps 7" long.

Now to be perfectly honest, probably 20 or 25 years ago when my father told me that was how Remington made their barrels, I called "BS". I was wrong. At the time, the whole process didn't sound like it was feasible.

There is a very fine line between "Hobby" and "Mental illness"