I cant speak for duracoat, but I can give you first hand experience on painting a gun with Krylon and Rustoleum flat camo paints. If the surface is prepped right (sanded or hit with some type of abrasive to aid adhesion, and kept free of oils from your skin) then I wouldn't have any reservations about using Rustoleum or Kyrlon. If your looking to keep it flat and no sheen, use flat spray paint and also use a flat sealer. Valspar makes a flat clear aeresol sealer that you can pick up at lowes.