hi got some problems with my gun (its a 3d model(is not from COD)) so i colored it now it looks so : https://gyazo.com/725e437296e8eca83ba8bff4d7c48b8b  but it colored even my Scope and Mag. how do i color the Mag/Scope ?  
That is the Weapon i got : http://tf3dm.com/3d-model/cz805-bren-with-aimpoint-87596.html     THIS IS NOT FROM COD, That means i can post a link for that weapon, its created by someone not activision, so dont remove pls the Link, i readed the Rule nr.6 , its a Free to use gun

You have to asign different materials and images for each weapon mesh/part:

Main Body - Mag - Scope etc...

Look in the rar you have, I presume there are different textures there
 

You have to asign different materials and images for each weapon mesh/part:

Main Body - Mag - Scope etc...

Look in the rar you have, I presume there are different textures there

Could i add you in skype that you can help?

Absolutely