I think it would be cool if when you reach the iron age you could make some sort of flintlock muzzle loading gun, you would have smith a barrel with the anvil, and make other parts from casts of brass, mixing gunpowder and pouring lead balls. I think this would be an adequate evolution of power into the iron age, and the reloads would be quite lengthy, holding each stage of reload in the off hand until you ram it down, or maybe paper cartridges. Maybe some sort of flint replacing dynamic, powder horns for carrying more powder, different types of lead casts, different calibers of barrels and small cheaper gun and a larger bore expensive varient? My idea is pretty loose but i think it would be an awesome addition to the game