The secrets of creating and operating gunpowder weapons have been discovered in various corners of the D&D multiverse. If your Dungeon Master uses the rules on firearms in chapter 9 of the Dungeon Master's Guide and your artificer has been exposed to the operation of such weapons, your artificer is proficient with them.
Optional Rule: Firearm Proficiency
Raw data
{
"name": "Optional Rule: Firearm Proficiency",
"page": 9,
"level": 1,
"__prop": "classFeature",
"source": "TCE",
"entries": [
"The secrets of creating and operating gunpowder weapons have been discovered in various corners of the D&D multiverse. If your Dungeon Master uses the rules on firearms in {@book chapter 9|DMG|9|Firearms} of the {@book Dungeon Master's Guide|DMG} and your artificer has been exposed to the operation of such weapons, your artificer is proficient with them."
],
"className": "Artificer",
"classSource": "TCE",
"otherSources": [
{
"page": 54,
"source": "ERLW"
}
]
}