Question on bolt springs.

[FlipShot]

this was something that I allways wondered. it seems that all factory mags (lvl 7) come with a black bolt spring. and when you buy a parts kit the bolt spring is like a goldish color. why is this? are they using a new material for the bolt springs in the parts kit?

[Demobilized]

My old lvl 7 bolt spring is goldish, so maybe it is just a thing that changed over time. I would assume that they are made out of the same thing, just a diffrent color.