I picked up this salty M1 helmet many years ago when I was a kid. I guy I used to work for suggested it was a Marine's helmet - it being painted grey - but I've found no evidence of this and presume it's USN. He was a helmet collector himself though, was he right? Did the Marine's paint their helmets grey too? What would the K4 painted on the front stand for?
Its liner has SU72 inside it which I guess indicates its year of manufacture but I'm wondering about the age of the shell itself. If it is much earlier I'd like to get a liner to suit. It's a rear-seam swivel bale helmet with a heat stamp number 1227B. Any information regarding its age and likely origin would be great. Many thanks,