The bulk update request #4449 is pending approval.

create alias army_helmet (60) -> military_helmet (168)
create alias soldier_helmet (15) -> military_helmet (168)
create implication military_helmet (168) -> combat_helmet (138)

Reason: Same thing. Different words.
Military helmets are a type of combat helmet.
The military helmet tag has been used to refer to combat helmets worn by modern day soldiers.