Using black as a base colour, you're not going to want to splash it with colour; maybe 2/3 at most, otherwise your mod will be too crowded. Additionally, the colours you do use (in this case silver) should only be used selectively to highlight your base colour. In the example above, I only used silver on less important features and in-between major pieces (body/scope). If you're going to make a simple mod like this, you probably shouldn't splash too much colour around. I used a rainbow-y scope to contrast it with the dark body.
If you want to use two base colours, or make something more colourful, you shouldn't just use a solid colour either, unless you want to make it really bland. You want to infuse the mod with a combination of both these colours, without one splashed on top and overpowering the other (unless it's by proper design).
This is just showing you what you can do with the AK series with proper planning and placement. Once again, simplistic base colours are used, meshed with a bit of colour.
My true point, after going through all of this, is that simplicity is often better than using a large array of colours. If you want to use a colour as your base, then by all means do so, but remember to use colours that are so vibrant they detract from the mod.
Tron style should only be one colour. (blue, red, green) And it should have very bold outlining not colours all over the place.
LIke it (:::::
Looks great A bit more work on edges but very good