Well I just managed to get it to go bang.
I had to take the bolt out, wedge a live round under the extractor rim then load both the bullet and bolt as one unit from the rear.
The live round had the bullet seated way out to be into the lands, so as to hold the cartridge against the bolt face.
Holding the bullet in place I chambered it and got it to fire. I don't mind saying that I was shitting myself as I pulled the trigger.
Man that case stretched. It now has a very short neck. I would say that the case shoulder moved forward over 0.080".
I rang the gun smith and he is going to fix the problem, right away.
This is a good way to develope a bad flinch.