Hm, not sure which part you're talking about but if you mean the light grey at the back of the gun, I think that's just a grey area that my black undercoat missed. The tiny red line on the first pic isn't paint, while taking the photo I think one of the bits of grass was stuck on the model, removed that afterwards. Aside from that, the colour of the gun is just undercoat black mixed with the green and brown at the tip.
Oh and that camo idea sounds good George, I might do that for my stealth units. Honestly, I really hated the grass, it's a mess to try and use, the sand was so much easier so I may just go with sand and paint it green or something. Otherwise it could be interesting sticking grass on certain parts of my stealth units to make some sort of gillie suit. The green/brown/black scheme seems to work well though, and since the main reason for Tau colours is camouflage, I can get away with using this scheme while staying in the lore limits. Hell, I might even create a custom backstory for my army since I'm not trying to make them like the other Tau paint jobs. Perhaps they can be a cadre that split away from the main force and eventually became mercenaries, working alongside their Kroot mercenaries for personal profit.
