The bolt should not close but often does close on the No-go gauge. If yours does do not worry too
much. This means there is more headspace than the GO, but it is still safe for military arms.. If the bolt does close
on this guage make sure you test with the field guage. It should look similar to photo below below.
The field gauge is the most important for the collector. If the bolt closes on this guage you should not fire the rifle.
You could attempt to try other bolts to see if this corrects the problem, but more than likely you will need a new barrel.
The rifle should never close on this gauge and should look similar to the photo below.