Ron's Gun Shop, Oshkosh WI. They do all of the bluing, the guy's name is Paul, he has spent a great deal of time researching and replicating the original process. We talk from time to time, and I rag on him alittle about color match, but the truth is some come out perfect and some are a little off, this is the nature of the beast. As we get further into this we can begin to match up different batches to get color closer, he is working on getting a more consistant process and we are doing what is needed on our end to give him consistant parts to work with. The heat treating point is true, the slide is heat treated and the receiver is not, this adds to the issue.