Gefunden im Internet:
"US ARMY HELMET
Helmet designed to replace British style helmet to give better protection to wearer.
Designer Hale and Kilburn of Philadelphia didn't take into account shape resembled that of the enemy and troops didn't like the idea of being shot by their own side.
Helmet made of Hadfield Manganese and weighed 2lbs 10 ounces , helmet is sand / saw dust finished very much like WWII M1 helmet."
Im Fundus des historischen Materials der Schweizer Armee liegt seit den 20er Jahren ein gleiches Modell!