Page 128 of Player's Option: Combat & Tactics (book number 2149) gives an overview of the Armor Class of various types of armor and pieces of armor so you can assemble your own suit of armor. Instead of giving a flat value you get a number you substract from your character's unarmored Armor Class (for most PCs this is 10). This also lists a nubmer of composite armors (pre-assembled armors that can be combined with other pieces) and shields granting a bonus to one's Armor Class.
However, I'm not too sure about the helmets listed. Insttead of giving a number to calculate your Armor Class with it seems that this suddenly shifts to what might be normal Armor Class values. I checked the rules for assembling your own suit of armor (p. 146), but this does not seem to be mentioned.
I suspect that this is the Armor Class used for the head in case of a called shot to the head. The numbers in some cases add up (leather armor and a leather helmet both grant an AC of 8, chainmail grants AC 5 and full plate with a great helm gives AC 1), but I'm not 100% sure of this. As such, I ask if my interpretation of the rules (the AC listed for helmets is the AC used in case of a called shot to the head in lieu of a character's normal AC) is correct, or did I miss something?
