Reviving an old thread maybe to refresh resources or take it on another tangent. I looked at the balistics site and they still sell the powder. Midway does not, or I can't find it. I looked on amazon and ebay and due to the arts and craft world I found many colors of mica.
You can get 12 colors from ...sh, china, for under 5 bucks.
It would be a kin to powder coating...lol. Then talking to my wife she brings a container of purple powder mica from her make up.
I just happen to need to make some new 303brit. May have to try it. and it was free!!!