Thanks for the info guys, Emailed Lauer and they suggested a .5mm or a .8mm tip. The only tips I've seen that small are for air brush's Most HVLP automotive style guns only go down to a 1.2mm unless you get a touch up gun and then you can get down to 1.0mm. I just can't see putting a base coat down on an entire AR using a air brush. I'd probably go crazy and use it the 223 on my self before i finished.
Don't have a touch up gun now, maybe I'll have to get one. Cant see using Krylon on any metal surface of my guns. And at 17.00 for 4oz, Ill have a hard time playing with a HVLP w/ a 1.3 tip to get it to lay a good coat.