I've heard that the rustoleum metallic aluminum works fairly well as the base. The main green color for the dome and the cheeks is spruce green, but as I can't seem to find that I'm going to try moss green instead. The green color on the back of the helmet is hunter green, and the main red color for the mandibles is claret wine.
I'm still currently looking for a good yellow and orange for the kill stripes, and one color that continues to elude me is the small amount of purple on the visor.
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Hope my (incomplete) list helps