Here we list you two kinds of Gun Units in Atlantica, have a look.

1) Inventor: Can be hired at level 84
Str: 160
Dex: 240
Def: 200
Int: 275
Vit: 190
M.Def: 400

Skills(Atlantica Gold)
Summon Machine Similar to a Beast Trainer's Beast Summon, they can summon the aid of machines to damage your oponent. Unlike the
creatures a BT summons, the machines can be made by crafting; they can also be purchased on the market.

Notes
Great Gun Unit. Good Defense/mDef and very useful. (Little information until obt)

2) Janissary: Can be hired at level(Atlantica powerleveling) 96
Str: 157
Dex: 247
Def: 198
Int: 225
Vit: 173
M.Def: 225

Skills
Shooting Stance Damages a single unit very heavily.

Notes
Deals more damage than an Inventor. (Little information until obt)