Aluminum is a lightweight, durable metal commonly used in firearm manufacturing for parts such as upper and lower receivers, handguards, rails, buffer tubes, and some barrels. Its corrosion resistance and strength make it ideal for AR-15 and AR-10 platforms, as well as handgun frames and accessories. Aluminum parts work with standard AR-15/AR-10 components, Glock and 1911 pistols, and various mounting systems, offering a balance of strength, weight savings, and reliability for custom builds and upgrades.