I want to add a bit more clarification after my second post where I reported that several new bolts wouldn't close on the no-go gauge with this rifle.

On testing the same bolts again, this time without a headspace gauge, I found that none of them would close or even begin to close. On close examination I found that this is because the bevelled edge at the rear bottom of the right bolt lug will not clear the receiver to begin turning down into the bolt lug recess. The bevel was sufficient on a couple of other bolts to permit them to do this. This tells me that the receiver casting is somewhat off spec in this area.

I also noticed two circular bright spots on the inside of the barrel cone which were obviously created by the front edge of the bolt face making hard contact here. Still going to roll off the barrel and examine the bolt lug recesses for signs of setback as the original bolt that the rifle was fired with shows headspace in excess of the field gauge.