Looks like a very bad machining problem. Rifle doesn't go all the way around. Is it a metal ridge at the transition of the forcing cone to rifling?
As best I can tell, there is a shiny ring all the way around the cone just before the lands begin. This is where the bullet appears to contact the major diameter of the barrel and I don't believe it is correctly machined. At this point it doesn't make any difference anymore as I have installed a new Criterion barrel ( which is a thing of beauty by-the-way) on the gun and I am headed to a private range tomorrow to dial it in. I was very pleased to see that the forum boss placed an article in the Bulletin a couple days ago which reflects my situation exactly. The factory barrel on this gun is very disappointing and I am not going to waste any more time or resources on it. Someone may want it so they can re-chamber it but it's not going to be me. It may shoot great if it gets re-chambered to 6mm Rem by someone but I'm done with it.
Mike