Ed,
1600F is way to hot a temperature for case hardening. At this temperature you are likely to get warpage. When I recase harden an action I first anneal it at 1450F then do any repairs and polishing. I then pack the parts in crucible with bone and wood charcoal. I heat the parts to 1350F and quench at between 1150F and 1250F. I know some who use slightly higher temperatures with excellent results. The colors you get with a torch are temper colors. Using a torch will soften the action in areas. This will not cause any serious damage unless done on an assembled action (I hope at least all of the springs are removed before torching). It just leaves you with an ugly gun. Torch colors have more yellows and purples and tend to have bullseyes of color than true case colors. True case colors have more greens. Torch colors should be represented for what they are and never as case colors. With a torch it is impossible to control the temperature so a description of "carefully controlled heat process" is fraudulent.
