During the Late Intermediate Stage of Atlantis, the compound of Gunpower had been discovered by mixing Saltpeter, with Sulfur. The Alchemist tested the compound, and after sometime found that it had both Explosive, and Pyromanic qualities. Within time this compound eventually lead to inventions such as the Fire Siphon, Arquebus, and Cannon.

The Musket was first invented after a Blacksmith improved a Arquebus by replacing the large trigger, with a forefront (before the stock) trigger and trigger guard, replacing the wheelock mechanism with a Flintlock mechanism, creating grooves in the barrel for improved accuracy, and finally
creating, and supplying u-shaped Orichalkos bullets to replace the Lead-Iron Arquebus balls.

The Musket changed Atlantean ranged combat to an extent, however Gunpowder was only produced by a single armory, which along with the flow of Saltpeter coming from Atlantean colonies in the Indian subcontinent (From the local Elephant population would prevent the Musket from truly changing combat forever)

The Musket was however without it's benefits, of range, and power, the powder was at risk of catching fire, or exploding in storage, and the Muskets were loud, and had to be fired in volleys to be effective.