I'm about 1/4 of the way through my first true rust blue and am using Brownell's own formula. I'm doing the barrels for a .303 British double that I've just finished building. So far so good. I did have to turn on the light bulbs in the bottom of my drying cabinet and add a pan of water in order to get good rusting. In the past I've always used Herter's Belgian Blue. My big problem with mixing your own is that almost all of the formulas, including most of Angier's are way too vague on the strength of the various chemicals. "nitric acid" doesn't cut it. Is it 10%, 20%, 50%, or what? Makes a huge difference!
