Jon, have you tried the Brownells classic rust blue? That may be in stock. I have been using it and it gives real meaning to the term blackening. I mean the metal comes out black. No hint of blue color no matter what the light conditions are. Don't get me wrong, it looks great. I did a set of Baker barrels and a 1890 and 1906 Winchester recently. They look really good but I was wondering if the Plinkton might have a more blue color that would better match what Winchester did. I've used the Herters fast rust method Belgium blue for years and that always delivers a nice job. I've used both the old formula with mercury as sold by Herters back in the day and the new formula without mercury and they seem to work the same.
