Nice one, Grav.
Weaponry from this period is really interesting. There's a link on that wiki page to an older design for a repeating firearm that was much lesslike a 'machine gun' but actually allowed for faster firing. Trouble was it was way expensive to make, and way to sensitive to adverse conditions. basically, the slightest damp on the powdr woud totally bollox the gun.
https://en.wikipedia.org/wiki/Kalthoff_repeater
No good for mainstream army use, because of the way firearms were mass produced and distributed. Basically - for largescale use, the separate coponents were each mass produced and then assembled, but with something like the Kalthoff repeater, the tolerance for any size or shape variation was so tiny, it just woldn't have worked on that scale. For the standard musket there would still have been problems mixing and matching components, but they had greater tolerance for variation, so far fewer rejected components. Also, much more reliable in adverse weather conditions. Even so, there are countless examples of inadequate guns, and rejected components.