Denmark captured, 1940.
Norway captured, 1940.
Luxemburg captured, 1940.
Belgium captured, 1940.
Holland captured, 1940.
France attacked, captured, 1940.
Evacuation of BEF from Dunkirk, 1940.
Battle of Britain, 1940.
Blitz on Britain begins, lasts 3 years, 1940.
Bankrupt Britain alone now, only defence a single Canadian Division and Monty's 7th Div, fresh from Dunkirk. 1940.
Very tense and very iffy and very ugly times, truly desperate.
Thanks to Government interference and lack of action, Britain had only ONE arms plant: Enfield. It had two lines, large and small. The large line was between jobs and could not make ANYTHING. The ruling Government would not issue ANY contracts to companies to make weapons..... and thy were 130,000 Rifles short, just from Dunkirk..... and they needed several million more...... and they needed pistols, revolvers, machine-guns, SMGs, ground MGs, aircraft MGs, weaponry..... and it ALL was supposed to be built in the small line at Enfield.
So they made what they could, as fast as they could and they instituted PERCENTAGE Inspection to try to speed things up even a bit.
THAT is what your gun is trying to tell you.
Then Winston was brought in and a lot of things changed, very fast. Churchill at least knew one end of a gun from the other and he understood that manpower without gunpower is meaningless. So things got worked out very quickly, to say the least.
But you already know that part of the story.