This is quite the unusual early-WWII U.S. front seam fixed loop M1 helmet shell. Its heat stamp of 11AA is contrary to what is normally understood about McCord manufactured helmets; heat stamps began around the mid-20 range and were followed by a single letter. This helmet's heat stamp is most likely a factory error, making it relatively difficult to date; however the helmet exhibits early style fixed loops roughly dating its production from late-1941 to mid-1942. It retains its original olive drab factory paint, cork texture, and brass-buckled khaki chinstrap.
WWII Fixed Loop McCord M1 Helmet Shell (Rare Heat Stamp)