We've used duracoat for refinishing everything from guns and knives to motorcycle and Jeep parts. Very durable and pretty easy to use.
As mentioned above, prep-work is the key. Lauer now makes a "shake n spray" kit with everything you need on one package.
If you dissassemble the gun, mask off any areas that are threaded, tight tolerances, etc.
It's alot easier than you think , just take your time and be patient.