At 3rd level, an artificer gains the artificer specialist feature. The following option is available to an artificer, in addition to those offered in unearthed arcana.

Rifleist

A Rifleist is an expert marksman that uses magic and engineering to gain the leg up on its adversaries. They concentrate on weapon infusions and are not afraid to do the dirty work themselves.

Rifleist Spells Starting at 3rd level, you always have certain spells prepared after you reach particular levels in this class, as shown in the Rifleist Spells table. These spells count as artificer spells for you, but they don’t count against the number of artificer spells you prepare. Rifleist Spells Artificer level Spell 3rd magic missile, ensnaring strike 5th misty step, cordon of arrows 9th conjure barrage, lightning arrow 13th greater invisibility, storm sphere 17th conjure volley, swift quiver

Thunder Cannon At 3rd level, you forge a deadly firearm using a combination of arcane magic and your knowledge of engineering and metallurgy. This firearm is called a Thunder Cannon. It is a ferocious weapon that fires leaden bullets that can punch through armor with ease. You are proficient with the Thunder Cannon. The firearm is a two-handed ranged weapon that deals 2d6 piercing damage. Its normal range is 150 feet, and its maximum range if 500 feet. If you lose your Thunder Cannon, you can create a new one over the course of three days of work (eight hours each day) by expending 100 gp worth of metal and other raw materials.

Arcane Magazine At 3rd level, you craft a leather bag used to carry your tools and ammunition for your Thunder Cannon. Your Arcane Magazine includes the powders, lead shot, and other materials needed to keep that weapon functioning. You can use the Arcane Magazine to produce ammunition for your gun. At the end of each long rest, you can magically produce 40 rounds of ammunition with this magazine. After each short rest, you can produce 10 rounds. If you lose your Arcane Magazine, you can create a new one as part of a long rest, using 25 gp of leather and other raw materials. This feature is not effected by your Tools of the Trade feature.

Thunder Monger At 3rd level, you learn to channel thunder energy into your Thunder Cannon. When you hit a creature with a ranged weapon Attack, the creature takes an extra 1d6 thunder damage. You can deal this extra damage only once per turn. This damage increases to 2d6 once you 14th level in this class.

Effortless Infusion By 6th level, your familiarity with your Thunder Cannon allows you to infuse it without effort. Whenever you infuse your Thunder Cannon using your infuse item class feature, you may choose to infuse another weapon with the same infusion. Infusing your Thunder Cannon this way does not count to your infused item maximum.