I know in the past a few people have asked how us omegans turn those garish neon nerf guns into something that looks less 'toy' like.
It's amazing what a simple repaint job will do.
To date, the best substance I've come across for recoloring the plastics that are used is this:
http://www.caswellplatin...m/vht/vinyl-fabric.html
It's a spray based dye that's designed to recolor Vinyl. Most of the plastics used in the nerf guns is PVC, which is Vinyl based.
It goes on light (when misted onto the prop) and wears -very- well. JD's new pistol is a great example of this.
The other spray we usually use is the Krylon ultra-flat paint, which is designed for camouflage use. The only downside to this is that it does not wear as well as the other, and will allow the underlying color to show on high wear points (like the bipod on LC's rifle).
As far as -how- to paint them, it does require a bit of dissembly, as you want to make sure that any and all moving parts are painted separately.
Most internal parts, obviously, should not be painted, and care must be taken to ensure that the inside of the barrel remain free of paint as well. A piece of rolled up newspaper or paper towel usually works nicely. However if you are fully dissasembling the gun, simply removing the barrel works much easier, and keeps the 'Please dont shoot me Mr.officer' orange color.

LC Sullivan
Omega Reef Marines
Omega Prime
Imperial Mercenaries Guild/Archonium
Military Union Commander, Asylum branch
To secure peace: Prepare for war.
If someone tries to kill you, you kill them right back.
Sometimes a sword is better left unused.