My S400 suffers from the infamous mediocre blueing on this model and I'd like to try using a proprietary gun blueing product on it. After all, it can't turn out worse than it started ... can it? I would therefore like to hear the members' experiences of using these preparations and how successful the outcome was, and how easy these products are to use. For example; is it a matter of putting plenty on, leaving a while, and then removing the excess. Or, is it more exacting than that. Let rip with your praise or condemnation of this type of product and name names, who makes "the good stuff" and who does not. Regards ... Geek