What's the difference between Rear Seam and Front Seam M1 Helmets?

[MedicalAmmunitionCrate]

Alright, so, I been looking around and saw there were Rear Seam and Front Seam M1s. Is there a reason the Reathr Seam and Front Seam helmets were produced differently? I am just curious.

[earlymb]

The most commonly heard reason is that if the rim suddenly came loose from the helmet, the front seam could be a possible danger to the eyes of the wearer, so it was moved to the back. I'm not sure if that's the real reason, but I guess production-wise it doesn't make a difference.

[HARRY THE MOLE]

That seems a sensible enough reason!

[plumbob]

It seems to have migrated to the back around the time when they change from stainless steel rim to manganese steel rim late 44. Perhaps instructions may have been given to move it to the back at this same time. I have never read anything as to why. But what earlymb states makes sense. There are the odd examples of rear seam stainless rims and front seam manganese so perhaps it wasn’t to the rule at the beginning.
Rod

[Rakkasan187]

There is some very basic information about the reason the rim changed from front to rear in the book "The M1 Helmet, A History of the U.S. Helmet in WW2" by Mark Reynosa, page 23. When the helmet was changed over to the manganese rim "it is probable that another production change or substitution was also enacted, which required the butt of the rim to be placed in the rear of the helmet body, as opposed to the front of the helmet body."

There may also be additional information in the 2 book series Steel Pots by Chris Armold. (The spelling is correct, Armold not Arnold) I will look later today when I get home from work.

Smitty

[Chickenpuffball]

Don't know why they moved to the back, probably because it made them easier/cheaper to produce. I do know however that they changed the material of the rim from stainless steel to manganese steel. This is why you can see fading paint on earlier M1 rims and you'll never see it on M1s from November 1944 and after.

[denfly]

I have a McCord rear seam stainless rim with heat stamp number 164F, swivel bail.