No point throwing pebbles.
To anyone watching this it is far easier to paint your gun as a whole and not in pieces. Simply use masking tape to protect anything (ie muzzle, glass on optics) you don't want paint on. This produces a much better result than when disassembling and spraying each part individually. Any patterns/colour you apply will flow better from component to component this way.
Make sure to read the directions and test the spray can first on the cardboard, don't use it on the gun you're painting without testing first in case it drips or you get blotches. Be sure to flush out the nozzle after you're done painting so it doesn't clog, typically accomplished by holding the can upside-down and releasing a blast of pressurized gas for a couple seconds.
Paint in smooth passes approximately 1 ft from the object to create an even base coat. For the snakeskin pattern start off with a light layer then using netting spray darker layers on top of it. If you want a foliage (depending on colouring) use green as your base then throw some grass, leaves on the gun and spray on brown/tan as you like.