This will document some interesting things about the M1 Helmet that might be germane to reenacting. The images below unless otherwise mentioned come from two books –
The M1 Helmet: A History of the US M1 Helmet in World War II. by Mark A. Reynosa, 1996. Schiffer Military History, Atglen, PA. Images from this book are marked MR.
The M1 Helmet of the World War II GI: A Reference based on the M-1helmet.com collection. by Pieter Oosterman, 2010. Schiffer Military History, Atglen, PA. Images from this book are marked PO. To view part of the collection please visit M-1 Helmet.com
M1917a1 Helmet
The M1917a1 helmet is the same m1917 helmet design but with an improved liner.
Steel Helmet Production: The Helmet, Liner, and Straps
M1 Helmet Liner Manufacturing Companies: How to ID
Paratrooper’s Helmet
Helmet Camouflage and Nets
Field Modifications and Field Markings
Identifying your Helmet
GIs would write their name on the liner or chinstrap or etch it into the metal of the helmet itself.
Medic Helmets
Unissued Liners
Below shows how the liners were packed from the maker.