Hoping someone can be of assistance.
I have an Italian M33 Alpini (artillery) helmet with several markings.
First is the ‘57′ on the liner which I know is the circumference size.
Secondly on the rim at the rear is stamped ‘P5′ which is apparently the production/batch number? ‘P’ referring to the Pignone factory in Florence?
Next, on the leather liner stamped in red is ‘AT’ a ‘Crown’ and the number ‘7′. ‘AT’ referring to Arsenale Torino? Not sure about the ‘7′.

Were the shells and liners manufactured in 2 separate factories or do I have a non-matching pair?
Also can anybody shed any light on the ‘A.S. 1936′ stamped into the chinstrap and the meaning behind the number ‘32′ on the Nappina? Battalion or Regiment I’m guessing.
Lastly, is there anyway to work out the year of manufacture? Is it the year stamped into the chinstrap (1936)?
Thank you in advance.