If your painting it black. I'd use Krylon Semi-Flat Black. Not too dull and not too shinny.
If you're going for an "earth color" I like the Krylon Fusion camouflage paint colors.
Remove the slide from the glock.
Spray paint in breif strokes, holding the can about 10 to 12 inches from the gun.
Hopefully this also goes without saying, but remember to mask off/ remove the innards of the slide before you start painting so you don't mess anything up.
I've had great experiences using Krylon ultra matte paint, but be sure to let it dry long enough so it won't wear off as fast.
Threepeat! AP Gearwhore of the Year. WWGFD? Adjective noun is adjective.
You guys realize, he's probably asking how to paint over the orange paint on the tip of the slide? To quote, "I'm in need of repainting SOME AREA on my glock 18c (metal slide). A responsible adult would already know how to do this. My 2 cents-peace.
I don't think he is just asking about the orange tip. I think he pretty much wants to match the gun's original finish and wants to know how to do it. Since I have been painting a lot lately I have wondered if there is a way to closely match the original black paint on my pistols. Don't use the Krylon camo ultraflat. it is too dull and therefore looks 'painted'.
"We are like butterflies who flutter for a day and think it's forever." -Carl Sagan