Welcome! US M1 helmets are a whole different ballgame than the German ones. One-size-fits-all, constant upgrades and refurbishments, and they stayed in service for 50 years. Know about the rim seam, the types and date ranges of the various chinstraps, and how to date a helmet liner. My guide for dating shells, feel free to ask me for clarification on any item.
1941-1944 sewn-on OD3 (khaki) web straps (WW2), front seam, fixed loops/bales/bails
1944-1951 sewn-on OD7 (dark green) web straps (late WW2-Korea), rear seam, swivel loops/bales/bails
1951-1960 OD painted buckles attaching web straps (Korea-early Vietnam)
1960-1973 black painted buckles attaching web straps (Vietnam era)
1973-1990 angled clip-on nylon straps with snap-on chinstrap
[I use 1990 as the end date because I wore one in basic training in 1990, but only saw Kevlars after 1990]
These dates are when the styles changed, but earlier ones remained in the system. Conversely, a shell with angled clip-on straps was not used in that configuration PRIOR to 1973 even though the shell itself could have been produced during WW2 as shells were constantly repaired and repainted over the years.
Edited by MattS, 05 September 2019 - 05:21 AM.