What is the purpose of the lugs that protrude from the sides of the M16 helmet?
These serve two purposes. They are mounting points for the heavy brow plate that was designed to be worn with the M16 helmet. This brow plate was meant to be used by soldiers whose job (observer, machine-gunner etc…) required that they be more exposed to enemy observation. The other purpose is an air-vent. That is why these lugs have holes going through them. Related to this question is the purpose of the rear split-rivet having a thicker head than the two front-side rivets. This was meant to keep the leather brow plate retaining strap from moving upward during use. Photos of the brow plate in use.
