I've got gold for all my gun apart from the receiver (the best bit). I managed to unlock all the other gold parts just playing the game casually but for some reason this is taking FOREVER. I regularly cap falgs so i'm always on objectives, and I always go for headshots when I get the chance. It's been about 3 weeks now though and the progress bad just won't move from 1/4 of the way down. Are all the gold skins this difficult and drawn out to unlock?