Musket

Three Gypsy Musketeer armed with Muskets guard the path to the game's 1st boss, and a 4th Gypsy musketeer will shoot at you during the fight with the game's 2nd boss. You can take their weapons from them after you kill them.

The musket behaves almost exactly like the Flintlock Pistol. The two use the same type of ammo, both can only hold 1 bullet at a time, and both require the same amount of time to reload between shots. The musket does somewhat more damage than the flintlock pistol, but the additional damage really isn't that significant on easy and medium difficulties.

Any enemy that can survive a single shot from the flintlock pistol isn't going to be killed by a single shot from the musket. On nightmare difficulty however, there is a notable difference, where the musket will kill a Ghoul in one shot, unlike the flintlock pistol, which takes two shots. Due to how common Ghouls are, this makes the Musket vastly more useful on nightmare difficulty. Otherwise the flintlock pistol and the musket more or less interchangeable, although the musket is considerably more accurate at long range (although you'll almost never find yourself fighting anything at long range in this game). Aside from the above, the only enemy in the game that the musket makes a difference for (on all difficulties) is the Gargoyle. A Gargoyle can survive 3 flintlock pistol shots, but dies after only 2 musket shots.