The nice thing about krylon is that it's easy to do touch-ups. I've used it and am surprised at how it holds up. Prep work is key, remove all wax, grease, oil and don't touch bare metal with your hands before paint. Use a good degreaser, a tack rag and a metal primer.
I just got done refinishing a .22 that had seen it's share of abuse, but I didn't krylon this one. I used Alumahyde II from Brownells for the metal/aluminum parts. As an epoxy paint it's more durable, but it has a much longer cure time.
For filling pits and such I use JB Weld "Kwik Weld" and sand smooth. No priming needed with the Alumahyde.
