RCS,
Question on your chinstrap. Are all the metal parts black or OD. If your metal is OD then it is a chinstrap added during the Korean war up to 1960. If it is black, then it is a chinstrap used after 1960.
The beauty of the M1icon is that they are issued in three parts and not a single helmet as Britishicon and Germanicon helmets of WW2 were issued. The soldier was issued the helmet as a steel shell, a liner and a sweat band. The sweat band was designed to accompany the soldier thru different postings, and the helmet and liner were turned in by the soldier when he left the unit. The helmet and liner were reissued to a new soldier but not in the same combination. In its lifetime a steel helmet may have several dozen liners used in it. A WW2 steel helmet may be used all the way up to 1988 when they were withdrawn from service.

At Ft. Benning in 1977, I was I issued a glossy black instructors helmet that had a front seam, stainless steel rim. It was a WW2 issued McCord shell that had been used all those years. It's served all the way up to the M1s being withdrawn from service. I still have that helmet in my collection.
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