Agent23
Ни шагу назад!
yeah, for a decent firearm you will need rifling and a projectile that conforms to certain aerodynamic requirements.They weren't. Percussian cap revolvers were. When those came about muskets were becoming rifles. 1853 Enfields and 1861 Springfields had sights accurate to over 5/8 of a mile with "this is going to suck" addressed "to whom it may concern" or "you".
I think the earliest is the Mine (fun aside, sounds like the Bulgarian word for handjob, and handjob balls I shall call them.)ball, which was at least Napoleonic era and I doubt it will work well for handguns.
Also, early gunpowder was pretty mad, lots of smoke, lots of noise and lots of fouwling up the barrel.