For making gun parts, the black is much better, because if the finish is scraped, only black shows through. White would spoil the illusion in that case.

I still want to get some of that low-temp plastic molding putty.

Anyone ever try Shapelock? It's pretty neat I've got a free sample of the stuff and you can just remelt it again and again. If you find their website they'll ship you a very small baggy of it for the cost of shipping.

That's the stuff! Shapelock, shapelock,...