Chambering has been outlined in two previous threads -
Artillery Barrel Specs
http://forum.lugerforum.com/showthread.php?t=21048
and -
Alternative Artillery Barrel Fabrication
http://forum.lugerforum.com/showthread.php?t=25858
- So I won't repeat the steps here. Stripped bolt is used to set headspace and breech gap. Barrel is then removed and the middle is rough turned. The barrel is also milled flat on all four sides where the rear sight base will be, and then is set back in the lathe to turn off the front sight base section.
(The battery in my digi-cam crapped out while the milling operations were going on; my apologies).