I painted my Stevens 200 the day I got it, too ugly to go in the safe without paint. Use Krylon Fusion on the stock for best adhesion, I use metal primer on the metal and scope for the base coat. Both are cleaned with alcohol, as are my teeth while I am doing the painting. I pack the optics with Kleenex and seal with tape, golf tee in the barrel end. Bolt closed. Base camo coat over primers. Reassemble. With snow camo you can leave the thing in different colors for the base coat, drape with grass, mesh, strips of cloth, yarn, whatever and spray the white paint over that and instant snow camo.
I also cut up one of my daughters white stockings and that stretches over the gun well enough.