Good afternoon, I’ve recently discovered that one of the original company’s that made M40’s also made the post war M52 helmet after the war. What I do not know is how to tell the difference since they look so identical. The M52 has the rolled rim and pressed vent but I am looking for the help of an expert to assist me. I believe I read somewhere it was to do with the vent but have been unable to find that source since. Can anyone help me out? Thank you in advance
