Yeah but with brass or cast iron bolts, that can wreak through armor. The comparitive energy of some of the crossbows can be as high as that as a modern 9mm handgun.
Just watching the show "Where did it all came from" from History Channel. The particular show is about firearms and how many of them originated in China. They showed the crossbows, and how the ancient Chinese refined the concept. Some featured among other things, a rifle like barrel, where the bolt is inserted inside, with a slit down the middle where the tension string can move. The barrel greatly increased the accuracy of the bolt. Another innovation is the use of grid lined up on both ends of the weapon---the first ever use of gunsights.
The heart of the crossbow are the precise metal trigger mechanisms. At the time of the Han, the Chinese already invented blast furnaces where they could manufacture these mechanisms in large numbers and low cost (where did we hear that before). At one time, the Han can have as many as 500,000 crossbows, and they issued crossbows to peasants and farmers like the way the US Army issues M-16s to troops. These ancient military industrial complexes also manufactured metal stirrups in mass. The stirrups enabled the Han cavalry to have a much stabler platform when swinging their weapons, firing their arrows or crossbows, travel much farther in shorter time.
They also showed the repeating crossbows and how they work. Essentially, the ancient Chinese invented the magazine, which loads of bolts are placed. The way to use a repeating crossbow is very simple, like you pull it down, aim, then release. It's all very user friendly. An expert user can shoot a bolt a second.
Later the program, when gunpower was invented, the Chinese got more devious, inventing things like MLRS, wooden carts full of large boxes that housed fire arrows---rockets with arrow tips. Thousands of these arrows were shot en masse. There were stuff that resembled grenades, gunpowder encased inside a clay ball, with sharp metal points around it for shrapnel effect. They also wrapped gunpowder packages at the end of arrows, to create a kind of arrow propelled grenade. Later when they invented cannons, they cased gunpowder inside hollow metal balls to create explosive shells. They made gunpowder based booby traps that were ignited using a flintlock mechanism when stepped on---the mine. They built huge metal cannons towed on massive wooden carts called the General cannons, which can range for a quarter mile. At one point, in the Great Wall, as many as 3000 cannons were placed to fend off the Mongols.
One of the chilling effect of all these innovations was that unlike other countries, warfare is quickly democratized in China. Being mass produced and user friendly, any peasant can use these weapons and kill with equal effect any rich noble. The result was that unlike other countries, China never developed a professional feudal or aristocratic warrior class (e.g. knights, samurai, etc,.)
