I used Brownells Gunkote on my 1911 frame. It looked good when I got done, not so much now. The frame is aluminum and from climbin up and down in my climber tree stand bangin it on the steel some of the paint has worn off, didnt chip off. It may sound like I abuse the gun but this is normal use for me.
It does hold up well if you dont use your firearm the way I do and be a little more carefull with it, GunKote does hold up well. I also did my Mossberg 500 frame and tube which has held up pretty great thus far. Only have about 100 round through it though and not much walking through the woods.
It is super easy to do if you know how to use a sand blaster, a can of spray paint, and an oven. I can post pics later if your interested, I dont feel like it tonight.