you cant build catapult parts and ballista parts out of adamantine.
I see, in the game, directly, with my own eyes, the options "Construct Adamantine Catapult Parts" and "Construct Adamantine Ballista Parts". I'm going to construct some for the heck of it, since it seems so absurd. I wonder which labor it uses... well, I guess we'll find out!
EDIT: Heh. "Urist McSiegeEngineer cancels Construct Adamantine Catapult Parts: needs metal logs." Now if only you could construct Adamantine Logs.
That, and as marksdwarves gain skill they hit the target more often. When a bolt hits a target, it's gone for good.
Actually, that's been recently disproved. Dwarves get XP for firing, not for hitting. 30XP per shot for a living target, something like 7.5XP per shot IIRC for an arcery range.
LegoLord isn't saying that - they're saying that (gain skill) -> (hit more), not (hit more) -> (gain skill). I misread the post that way too at first, but when you look at it more carefully, it turns out that what it says is correct and relevant.
Of course, it's quite convenient that they gain XP for missing - I'm also ending up with a bunch of Elite Marksdwarves without having to work for it
Funny thing - I drafted a bunch of new marksdwarves, and the goblins have been dying a lot more often. It looks like less-skilled dwarves are, ironically, actually more likely to hit in this situation. I must admit, though, that watching a stack of marksdwarves fire eight cyan bolts right in a row is really cool looking.