I use paint on a lot of my AKs, I use hi-temp engine enamel that is good to 550°F.
Here is the paint I use it is a bake on paint. http://www.vhtpaint.com/products/engineenamel/
I have done a test on this paint after curing, I used acetone on a scrub pad & couldn't get the paint to budge.
If everyone is thinking alike, then somebody isn't thinking. George S. Patton