Hodang those textures are looking slick already, I legitimately can't tell if you're using normals+spec, or if it is just a really convincing diffuse map.
Just realized that the barrel is too vibrant for a mil-spec, well I guess this wont win the game then. But I'll proabably finish it anyway just for the sake of it.
Now its just dark, the material itself needs to just be less reflective, and you need variation in the spec/reflection textures for it to look more realistic
Diffuse and spec textures if any of you is interested ;) Still interested if any of you know how to do a cool opaque glass shader in the marmoset toolbag ;)