URU SUBMACHINE GUN NON-FIRING DUMMY: parts, materials part 2

I have shown before the assembly, but perhaps this one is with more details.
Additionally, I have a different cap for the main spring- which will allow installation of the stock.

FOR ALL OF THE CONCERNED- this will protect my eye from the spring guide - not that it would ever matter: I am not planning to shoot this contraption , even from the hip.

Not in this tyrannical universe anyway.