Copper Tier adds a new tier of weapons, tools, and armor to Minecraft, balanced around a vanilla play experience. Copper tools can mine the same blocks as stone, but are closer to iron tools in durability and speed. Copper armor is stronger than leather, but weaker than iron; the same is true for weapons.
While copper horse armor is weaker than iron, it's slightly stronger than leather, and can be crafted like its leather counterpart.