Gun metal is basically a mixture of black and silver, giving it a metallic look on metal and it’ll look great on guns and metal parts. I even use the gun metal on the inner frame of gundam.

Since I use an airbrush, I use multiple layers of colors to achieve the look. First a black undercoat. Second: I highlighted the middle portion of the parts with Gun Metal added with a bit of white. The final coat is drybrushing the edges with aluminium silver.

Since I’ve almost finish the whole gundam, I’ll post the picture when it’s all done.