He developed the method with Tempilaq, and discovered that it annealed the necks but left the base pretty much cool.
That's definitely not the case with the 6.5 CM or .243 cases I've tried this with so far- I drop the case onto a damp towel as soon as it gets too hot to hold around the midsection, where upon it hisses for a second and starts to cool via ambient air and contact with the towel. However, enough heat transfers from the neck to the case head that the entire case gets what I'd describe as hot. I do suppose some 400 degree Tempilaq would be the way to determine whether my case heads are actually getting above the temp range I want.
I strongly suspect, though, that I'm not getting my brass hot enough to cause any damage or even fully annealing- I did some last night in a dark room and never detected the "red glow" guys mention by the time I was removing my cases from the flame, and the case heads were never hot enough to be painful to the touch. Also, as mentioned, brass still takes a considerable amount of force to resize.
