[Hectic]

after you prep pint the whole thing the lightest colour let it dry.
take some masking tape and some wax paper tape the wax paper end to end and over lap the next strip of tape efectively making a sheet of masking tape. Cut shapes out of this sheet (like the shapes you see on woodland camo) once the base cote/lightest color has dryed stick some of those bits in random places on the gun cover say 20-30% of the gun (adjust based on how many colors your gonna use) then spray the next darkest color let it dry stick some more bits on in random spots, continue this till you get to black (or whatever your darkest color is) let it dry have an exacto knife handy use it to lift the edges of the tape and peel slowly cutting through the painted edge of the tape if needed, once removed you can leave it as is or spray tue whole thing with a flat clear cote to make it last longer.
i like to use krylon ultra flat paints for both plastic and metal