There's a very big thread about this in the game balance discussion and paul did the math about arbalest damage on various amounts of armour.
(Raw) damage is randomised sligthly(0.9-1.0) but both of the following armor soak and reduce calculation armor is randomised by 0.5 to 1.0. So with higher the armor level the target has, the wider is the possible damage range.
Example:
MW Arbalest with MW steel bolts -> base_damage = 100p
against naked, point blank, body shot:
90 to 100 damage (aka certain death)
against 30 (body) armor, point blank, body shot:
55 to 81 damage, 67 avr, damage span = 81 - 55 = 26
against 50 armor, point blank, body shot:
38 to 70 damage, 52 avr, damage span = 70 - 38 = 32
against 70 armor, point blank, body shot:
25 to 61 damage, 40 avr, damage span = 61 - 25 = 36
As you can see, it can take as much as 3 point blank body shots to kill a target with 7IF and 65 armour.
When it's raining, it will take 1 or 2 additional hits.
Damage should be a lot higher than the better bows, but not THAT high (currently Arbalest has almost 4x the pierce damage of a Longbow - which is a joke, historically and balance-wise.
Arbalest deals just over 3x the damage a longbow does.
Arbalest does not get a damage increase from wpf and PD, which the longbow does.
Arbalest is about 3x slower in firing rate compared to the longbow.
In the end, the arbalest deals about 2x the damage of a longbow (after damage increasing effects) and is a lot slower.
Sounds balanced to me.
