Chu-ko-nu:

 
Weapon Type Cost Weight Size S or M Size L Notes Fire Rate S M L 0 1 2 3 4 5 6 7 8 9 10
Chu-ko-nu (repeating crossbow) 3 ch'ien (15 gp)
quarrel, single: 1 yuan (5 cp)
quarrel, two dozen: 1 tael (1 ep)
<>
quarrel, light: 0.1
1-4 1-4 - 2 5 10 15 -4 -3 -3 -2 -1 0 0 +1 +2 +3 +3

The chu-ko-nu is a repeating light crossbow, capable of firing
several bolts before needing reloading. Mounted on the top is a
magazine that can hold up to 10 quarrels. The cocking and reloading action is
worked by a single lever, pushed forward and then pulled back. This
allows a faster fire rate than normal. Up to two quarrels can be reloaded
in the magazine per round. Thus five rounds are required to completely
reload the chu-ko-nu. A character cannot fire and reload in the same
round. It is heavier than a normal crossbow and has a poorer range.



DMPrata wrote:

Ooh, ooh — I know this one! Light crossbows do less damage then self bows, and heavy crossbows do about the same amount, but take a look at the armor type adjustments. The crossbow generally has a better chance of penetrating a plate-armored foe.
 


At close range the heavy crossbow is deadly.
It's penetratin falls off sooner than that of the longbow, and the later had a longer effective range and a much greater rate of fire than does any but a repeating (Chinese) crossbow.
The repeating crossbow has poor penetration and short range at best, however.

Gary the Wargamer