I.Var Antiarmormode
It's a crossbow type weapon with "Automatic Crossbows"'s scripts form J3X.
so as an automatic firearm ,when you equip it and right click & hold it'll launch 4 rounds bullets, then second time will launch 3 rounds ,finally the third time will be launch 4 rounds and reload.
II.Var Meleemode
A greatsword type weapon.
III.20mm Antiarmor Bullets/INV
IV.20mm Explosion Bullets/INV
All can be forge in material Dwarven.
Credit
J3X-Automatic Crossbows
Ghosu-Project Flintlock Rifle