Trench Warfare (Ex)

Starting at 3rd level, a trench fighter can select one specific type of firearm (such as a machine gun, revolver, or rifle). He gains a bonus equal to his Dexterity modifier on damage rolls when firing that type of firearm. Every 4 levels thereafter (7th, 11th, and 15th), the trench fighter picks up another type of firearm, gaining these bonuses for those types as well. Furthermore, when behind partial, normal, or improved cover, a trench fighter gains an additional +2 AC bonus from the cover. 

This ability replaces armor training 1, 2, 3, and 4.