It's called Krylon, you can find it at Wal-Mart.
Just kidding!!!!
I'm just trying to get some attention. I know somebody knows something about aftermarket scope coatings. Cough it up or I'll insult again!
I like duracoat myself.
Okay apologies to Gameez for being snarky. My fear with doing it myself is my past knowledge and results with spray paint. I appear to have no knack for it.