Automatic Crossbow

                              In fourth century B.C., the Chinese developed a new kind of crossbow that revolutionized the way siege warfare was fought: here's a picture of what it looks like.

That's a feeder on top and the lever near the end is the repeating action. The repeating crossbow was the first semi-automatic weapon ever invented. Trained soldiers could let fly 10 bolts in 15 seconds before the magazine needed to be reloaded. Due to the nature of the action, it needed to be shot from the hip in order to fire that quickly. Oh, and the bolts were often dipped in a fast acting poison so that just a scratch could be fatal. Fighting in small teams reduced the risk of friendly fire.

Now, this is a cool little thing. It was invented by Chinese and was probably used already around 200BC! The most interesting thing is the fire rate. While normal crosbow can fire 1 arrow per 12-15 seconds (longbow has 1 per 5-6secs), this one was able to fire 10 per 15 secs=1 per 1.5 second! It was something like the ancient submachine gun (or more like bolt action rifle).
The most famous model is "Chu-ko-nu".

It has a magazine with 10 arrows (that rectangle thing forward) and is operated by handle in left hand and lever in right. The bow it's made from bamboo.

Release mechanism is quite simple and effective. It is known as the peg and hole release. The release pin (the peg) fits down into a stepped hole in the magazine base plate. It is T-shaped, with its bottom portion having a square cross section, 6mm on a side. Its height (19mm) is precisely equal to the vertical thickness of the magazine base plate. In this crossbow, the release pin and the hole have been precisely cut and accurately fitted so that, with only the force of gravity, the pin drops to its bottom with hardly any play.

Basically all you need to do to fire is operating the lever. The new arrows are added to the magazine through the hole in top. A hundred man with such crosbows could put 1000 arrows into the enemy in just 15 seconds. The verson with 2 arrows per shot was also made creating the impressive rate of fire - 2000 arows per 100 man and 15 seconds! Such storm of arrows could devastate the attacking army in few minutes.

However it had also disadvantages - it's power was not so big as arbalest or longbow and accurracy also sucked. That was the reason why it was used only on short ranges against massed attacks. The arrows were also often poisoned to achieve sufficent lethality (because the good armor could stop them easily). The max. range was 150-200 yards, with effective range only 80 yards.

The last time this weapon was used was against Japanese in 1894-1895!