I did a muzzleloader plastic stock
what I did, was remove all the bits and pieces and give it a good washing with soap (I find ALL plastics carry an oil on the surface)
then reassemble everything I wanted painted.
I then painted everything dark green, not too much, I can still see some black poking through
over that, I "LIGHTLY" went over with a fine mist of brown in a few stripes
THEN I took some leaves from my juniper, and laid them where I wanted them, and misted a matte silver over them... Minimal is the key here.
I did not prime my barrel, or etch it, and it being nickeled, is starting to chip, but the stock is like factory.
I used Krylon Fusion IIRC
I can lose my gun in any pine forest...