I spent some time modifying other gear leather/metal/combat armor, I got rank 1 of the armorer perk but the standard army helmet is not even showing up in the item list when I use a armor workbench.
What's going on there? Do I need further ranks or different perks? I didn't think so because other modifications are shown in the menu even if I can't craft them yet and other perks seem to be specific for other things like modifying melee weapons or guns.
Is it just that this item cannot be modified at all?
Doing the Railroad quests eventually unlocks a ballistic mesh upgrade that can be applied to a variety of previously un-modable clothing and headwear items. I'm not sure if the Army Helmet is specifically among them.
– T.J.L. Dec 08 '15 at 16:37