Here are a few links you can follow up on, first is Practical machinist, where I spend a lot of time:

http://www.practicalmachinist.com/vb/gunsmithing/cannon-making-lathes-big-ones-174974/

http://www.practicalmachinist.com/vb/ant...wash-dc-114825/

If you join up and ask, you probably see more photo and discussion. I have some pictures too, but would have to scan and then this forum will not host the pics. But the above PM, will host the image.

There is a lot of cross over interest, guys who like guns, like machines and tools all part of the same fascination for many.

Two images of boring & turning:

Closeup shot of boring a barrel: