Help with Custom 3d ranged item used by an entity

Essentially im trying to make a custom mob shoot a ranged item, but when that ranged item gets fired the bullet just shows up as an arrow and has none of the properties it is asigned to have in the triggers (like setting an entity or player on fire when they are hit by the bullet). The bullet has a 3D model and texture assigned to it so i simply have no idea why its not working