I got a Jennings J22 for cheap. The finish on the frame wasn't great, but the slide was perfect. After helping a friend assemble his blasting cabinet, I stripped the Jennings' frame and sandblasted it in preparation for Duracoat.
The media we used was black and very fine. That's all I can tell you about it. My friend picked it up at Grainger, an industrial supply company. We used a #4 tip on the Harbor Freight blasting cabinet with 40 to 60 pounds of pressure.
I should've taken the barrel off of the frame to begin with. I definitely hit the outside of the barrel with the sandblaster, which meant I needed to remove it anyway to polish out the roughness. With the barrel removed, I was better able to sandblast all portions of the frame.
I shot the frame with Snow Gray Duracoat. I used my friend's Badger airbrush. The airbrush took forever to spray the paint and got clogged halfway through. The finish went on very thin. I reassembled the gun (aside from the one missing pin that I lost in my friend's shop) and took a photo. I like the look.
I really think I may be the first person in the history of the internet to duracoat a Jennings. This is history folks, history.