Hey there .. Sounds like an interesting project ! .. You have several options re this venture .. Anytime you're painting most anything, always try to give the 'correct' paint some tooth to grab onto ..Several companies do make gun specific camo paint & will adhere better than a generic hardware store spray paint . You know the old adage: "when all else fails, read the directions" ( holds true just ask me ! ( lol ) .. in so far as patterns , that's up to you and you have many options ..you can do solid patterns/ shadowed / wiggly stripes etc; Main thing is the take your time, have fun & be cogniscent of the 'drying times' between applications .. that's my .02 & lord knows i've done a s--- load of them & every other kind as well ..( hope this helps you a bit )