The standard struggle for firearms designers during the age of flintlocks was to improve the shot count of each firearm. In an age where the sheer number of shots that could be fired in a minute had as much effect on the outcome of a battle as any tactics this really mattered.
One solution was to strap a bundle of barrels together, fired by a single lock to create a ‘volley gun’. Although this was a devastating weapon the recoil was ferocious, it took a long time to reload and it still did not have the same effect as the same number of shots aimed and fired separately, not to mention the sheer weight. The most famous example of this is the Nock volley gun, used by the British Royal Navy.
The next step was to equip each barrel with their own lock to fire them individually. The trouble with this is you end up with a very unwieldy weapon with lots of moving parts that require maintenance and is expensive to produce. You also still have the massive weight of all those barrels, plus the extra lockwork. It’s OK up until about two shots, but gets worse after that.
One example in military service was the Austrian Jäger ‘double-rifle’ (though it was in fact a rifled barrel over a smoothbore).
Harder than you thought this business!
Another option that caught on was to have a set of revolving barrels that you rotate to line up with a lock, which you prime for each shot. Still a bit of a faff but still faster than reloading a musket. Some were produced with self-priming pans (but more on that in a later post) to speed this up.
Mr Nock produced a variant of his gun on this principle, with six barrels rotating about a centre pin.
Finally someone had a really bright idea. Why not ram several loads down one barrel and set them off one after another? What could possibly go wrong?
Well if you fired the locks in the wrong order the gun would blow up in your face, but apart from that not much.
This terrifying concept was used experimentally, but as far as I know it was never adopted by any military force. There was too much to go wrong.
There’s quite a bit more to this story, this is just the beginning!