Mysterious Helmet from around WW1?

Question

Ok so I was at a military surplus store about 2 years ago and I came across a pile of Swiss M1918 helmets from around world war 1 to the 1950's, most of them were grey in colour but I noticed a black one. I purchased it and when I got home it was full of secrets. For one, the Swiss m1918 is ALWAYS grey, not black. They normaly have a rough gritty paint job to prevent it from shining or having any glare, this one was relatively glossy. To add to all of that, the initials H.M were carved into diferent places on the helmet (the chin strap, the top etc.) It is just very odd and I want to know more about it. Does anybody have any clue what the story behind this strange helmet could be?

I have some pictures to show you as well, here:

http://i292.photobucket.com/albums/mm23/Shenza1/FILE0166.jpg?t=1218910407

http://i292.photobucket.com/albums/mm23/Shenza1/FILE0165.jpg?t=1218910470

http://i292.photobucket.com/albums/mm23/Shenza1/FILE0171.jpg?t=1218910570

Please help me thanks!

Answer 1

Nope, I'm sorry but it can only be a Swiss M1918 or M1918/43 helmet.  If it was lacking the two air holes in the back of the crown then you would have a super rare Model 1905 U.S. made experimental helmet which never went beyond the prototype stage.  Many believe that it served as the design basis for the Swiss helmet.  If it is a M1918 it is about 90 (-) years old and if it is a M1918/43 it is 63 (-) years old.  I've seen my fair share of black and gray Swiss helmets over the years, gray ones were Swiss Army and black one were issued to the Swiss police and fire fighters.  

Answer 2

Looks like German Special Forces.

It may, but I know it's definitely German. You can tell by the way it rounds a lot.

Answer 3

H.M is properly his initionals