Why didn't this devastating machine gun dominate the world? This fires faster than early musketeers.
The repeating crossbow, with its smaller and lighter ammunition, had neither the power nor the accuracy of an arbalest, however. Thus, it was not very useful against more heavily armoured troops unless poison was smeared on bolts, in which case even a small wound may prove fatal.1 Since the repeating crossbow was shot from the hip, accuracy was poor, but the aim could be adjusted very swiftly since the next shot was only a second or two away. wikipedia
- Not very useful against opponents wearing armor
- Ten shot magazine
- Not very accurate
- Short range.
Rate of fire is meaningless if all the bolts are repelled by armor.
"Devastating" is not the only characteristic which makes a weapon useful. Already ancient Romans experimented with repeating ballistae, but there is no evidence of their use in battles. A weapon must be convenient and handy to use, and transport, and there are many other characteristics which make a weapon useful.
There are many similar examples in history. Type "Dardanelles gun" on Goolge or Wikipedia to see a picture of a Turkish 15 century cannon. You can imagine how devastating it was. But this type of weapon was soon displaced by much smaller guns.