I practiced on several cases before moving to these. I exposed the cases to heat for 10 seconds approximately 3 inches form the base of the torch. I noticed a few of the brass have the heat mark a little further down the shoulder than the rest. I was in a relatively dark room and noticed when I took the heat away from the brass most of them had the same dull red color to the neck. I would like to go test these with my full power load to see if I have helped or hurt things. Any observations or comments ?