they are ww2.
Model 17A1's. Early WWII.
A better liner system was designed and replaced in the older mdl 17's in 1936.
They are hard to find today.
Thanks Chris and SteveR ,
I am not a U.S helmet guy.
I wanted to get a WWII or WWI date on the helmets shown in the photo above because of the trench guns that are shown to the left in the photo.
The U.S. helmet shown below is the only U.S. helmet that I own.
Fixed bale, Westinghouse marked liner....am I right in assuming this is July 41 to Sept 43 vintage?
What else do I look for?
I am a gun guy and I bought this helmet to go with my U.S. WWII gun collection.
I can add that the helmet net is a US made 44 type
And you have a very minty liner there, very nice
To add to what has already been posted, your first photo is as stated, M1917A1 also refered to as a "Kelly Conversion" These were the the US WWI vintage M1917 shells with a transitional liner, much more comfortable than the original M1917 liners where were old and worn by the time the US saw itself heading into the war. The new liner of the M1917 was just to fill the gap until the production of the new M1's came up to speed and started to be issued in replacement to the aged M1917's.
The M-1 helmet in your second photo looks quite fresh and minty. Can not really see anything of the shell so would be hard to tell anything. As for the liner, I think it is late wwii or later, judging by the color of the webbing. Others will chime in for better clarification I am sure.
Thanks for your comments and help.
Recent photos in different lighting
Liner marking "27 with Westinghouse logo".