Elemental Weapon is a spell that's available as of level 3, with a castingtime of 1 Action for D&D 5e - Read up on all the spells on DND-Spells Dungeons and Dragons 5e - Spells, Tools, Spell cards, Spellbooks'. The damage increases to 3d6 at 6th level, 4d6 at 11th level, and 5d6 at 16th level. After you use your breath weapon, you can’t use it again until you complete a short or Long Rest. Damage Resistance: You have Resistance to the damage type associated with your Draconic ancestry. Languages: You can speak, read, and write Common and Draconic. Ignoring armor isn't the solution, especially since most firearm to body armor shots are going to be other than 90°. Using armor as a damage reduction rather than pure hit/miss is the best way to simply represent firearms damage.
Transmutation
Level: 3
Casting time: 1 Action
Range: Touch
Components: V, S
Duration: Concentration, up to 1 hour
The most basic motivation for an adventurer in a Dungeons & Dragons campaign is the desire to seek treasure.The monsters and villains in the world tend to keep the best stuff for themselves, which is why they often have a date with the end of an adventurer's blade. The 3.5e Dungeon Master's Guide has some rules for firearms in the Building a Different World section (p144). Page 145 provides details for Renaissance weapons: pistol, musket, bomb and smokebomb. It also provides some details and considerations for how gunpowder and firearms work.
A nonmagical weapon you touch becomes a magic weapon.
Choose one of the following damage types: acid, cold, fire, lightning, or thunder. For the duration, the weapon has a +1 bonus to attack rolls and deals an extra 1d4 damage of the chosen type when it hits.
At higher level
When you cast this spell using a spell slot of 5th or 6th level, the bonus to attack rolls increases to +2 and the extra damage increases to 2d4.
When you use a spell slot of 7th level or higher, the bonus increases to +3 and the extra damage increases to 3d4.
Page: 237 Players Handbook
A Paladin, spell