3. If you can, tie a string to the trigger guard and hang the gun from a tree limb so you don't have to handle the gun as you paint it. Thoroughly apply a coat of dark gray primer to serve as a good base. If the outer layers of paint get scratched, the dark primer will show through instead of wood or metal. Begin painting with flat spray paint, starting with a khaki layer over the primer. Use small limbs, leaves and cedar or pine boughs to build a pattern. Start in close with the spray can for sharp lines, working with the khaki and then adding black or forest green in layers of varying darkness.