It was suggested for me to cross-post this here.
So after losing one too many adventurers to wooden bolts through my iron helm, I decided to look into the issue.
I turns out that it is indeed a
bug, and after a couple hours of arena testing I have devised a bandaid solution.
Alright, I spent several hours testing this and messing with raws in the arena
Variables that changing did nothing:
size, velocity multiplier, penetration_size in item_ammo.txt
shoot_force, shoot_maxvel in item_weapon.txt under crossbow
What I finally settled on was that this bug is some underlying factor that maximizes the damage/force/velocity of these bolts, and I can't change that.
What I could change, and did, was the glancing. When I set contact_area in item_ammo.txt to 60 (instead of 2) then copper bolts only penetrate full iron armor in the upper arms and legs. This is a bad bandaid fix, but it is far better than what is currently in the game.
Wooden is useless against any kind of armor but still good against cloth/naked, bolts above copper still penetrate armor easily. I haven't tested these bolts vs adamantine.
https://dl.dropbox.com/u/1285839/item_ammo.txtHere is my modified raw. To install this fix, either change the 2 to 60 yourself, or download the text file and overwrite it in both your raws [Dwarf Fortress/raw/objects] and your saves [Dwarf Fortress/data/save/(region)/raw/objects]. If you're not sure how to implement this with a mod, I don't know either.