I use the actual Gun-Kote brand in either a flat or semi-gloss clear. I started experimenting with it several years ago when I was looking for something that would cut down on maintenance requirements for damascus blades. I tried it on a couple of damascus hunters, and a friend and I used them throughout a Montana hunting season. Found that its darn tough stuff, and it brings the maintenance requirements to near zero.
It took me another year or so before I figured out just how to use it on blades, but its become a staple in my shop. The biggest trick with this stuff is to apply it with a air brush, and in this case less, is more. If you just lightly mist it on it works great for blades.....if you apply like you would spray paint (actually can see that its there), you've applied too much. If you apply too much, it looks terrible, and won't hold up.