This is my 20th scale dual 0.303 Vickers machine gun. This is one in brass, one in low cost plastic (since broken, brass is best), the mount is in brass but the interconnecting structure couldn't be made in brass so it's in a nylon type material.
This particular Vickers machine gun was operated by compressed air, generated from the gun's recoil, these were originally designed for aircraft use but as they could not be synchronised to fire through the airplanes propeller and the Browning machine guns could, the Browning became the preferred weapon for aircraft use, leaving the Vickers more available in the UK for naval and other uses.