Gunmetal Rod Dealers in Ramnad Gunmetal is a type of bronze – an alloy of copper, tin, and zinc. Proportions vary by source but 88% copper, 8–10% tin, and 2–4% zinc is an approximation. Originally used chiefly for making guns, it was eventually superseded in this department by steel. Gunmetal, which casts and machines well and is resistant to corrosion from steam and salt water.Gunmetal is used to make steam and hydraulic castings, valves, gears, statues, and various small objects, such as buttons. It has a tensile strength of 221 to 310 MPa, a specific gravity of 8.7, a Brinell hardness of 65 to 74, and a melting point of around 1, 000 degrees Celsius.