Metallic Map not working?

I made a Metallic map for my Asset but it seemed not working but im pretty new with Metallic maps so is it that my map was poorly build and textured or there are some settings in ue4 That i Dont Know?

Metallic Map:

What It looked like with metallic Map:

Material Nodes:

Its A bit Ambitious but what im trying to achieved is this kind of effect in BF4:

And Also for a note if my texturing is bad and my metallic map texture is also bad please leave a note and critics

metal needs to be either ON (white) or OFF (black) so you will need a black/white texture for it.
Also you will need a roughness and normal map to make the gun look good.

Thanks For the reply and info and another question what is the function of roughness map since i never used one before and also how to make one?

Roughness defines how “rough” the surface is, which translates to how shiny/reflective it ends up being. You can test it out by hooking a vector 1 node into the roughness hook and changing the value between 1 and 0.

Unreal engine is a PBR (physically based rendering) engine, which uses specular or roughness (ue4 uses roughness) to define how rough/smooth a surface is.

it also means that none of your diffuse/albedo textures can have shadow-information.

its really hard to explain, so here are a few links that can help you: