Living Fortress: You gain proficiency with heavy armor. You gain the defense fighting style.
Brace: While using a shield, you may rest a firearm on the shield as a bonus action. While doing so, you may use a Wheellock Rifle and Shield at the same time. While doing so, you do not gain disadvantage on firing at creatures within 5 feet of you. You also extend the range of any firearm you shoot while Bracing by 20 feet.
Turtle Up: Once per round, as a reaction to being hit by an attack, you may roll a d12 and add your proficiency modifier. Reduce any damage dealt to you by the result. Additionally, you may add an additional two points of your dexterity to your armor class while wielding a shield and wearing medium or heavy armor.
Push Back: While wielding a shield, you may use your reaction to make a firearm attack against a creature that moves adjacent to you. If you hit the target, they must succeed on a strength check (DC 9+Prof+Dex Mod) or be pushed straight back 20 feet and knocked prone.
Holdout Expert: Your armor class does not limit your dexterity bonus to armor, and you gain resistance to fire damage as well as non-magical bludgeoning, piercing and slashing damage. If you have not moved since the start of your last turn, you gain resistance against all bludgeoning, piercing and slashing damage.