In pure mechanical terms, this all sounds like a matter of degrees but if you consider that weapons in RPGs are intended for adventurers, operating in small groups and fighting in skirmish type engagements, thee practicality of a musket suffers greatly. While their are historical precedents for the use of archaic firearms in skirmish engagements, these were still with groups of like armed men fighting in some form of drill and supported by other men fighting in a similar style.
A warrior, armed with a musket in a dungeon delve is unlikely to benefit from other firearm equipped adventurers. In addition, the smoke and noise of his shots is likely to prove distracting and hindering to others in his party. With their visibility obscured and the roar of a boom stick in their ears, a party may find spells difficult to use, and a lacking in the coordination and communication that the close quarters of dungeon combat would require. One or two shots and the already claustrophobic passage will now be choked with smoke as the orcs close range.
But Eli, what about pistols?
Pistols seem like the adventurer's best firearm. Lighter, more compact, and able to be carried in braces of multiple pistols, the pistol really is the choice firearm for the dungeon dweller. Sure the smoke and noise will still be a problem, but at least the reloading issues are minimized by the ability fothe warrior to carry a couple of pistols that he can fire early in the fight and then either fight with them as clubs or put them aside to fight with melee weapons, saving reload time for after and between fights. While the wizard is memorizing, the cleric is busy healing the fighter and the thief is distracted trying to steal gold from the party, the pistolier can be busy cleaning and reloading his braces of pistols.
Next time I'll look at the thematic, role-playing, and setting aspects of firearms as I see them.
Thanks for reading,