• The exact temperature of the stress relief is not vitally important, as long as it is within the necessary metallurgical range.

• The exact duration of the application of heat is not vital, as long as the final temperature is within the necessary metallurgical range.

• The amount of heat applied to each brass case per time interval must be identical to achieve the required uniformity of stress relief.

• A case annealing machine is the best way to ensure the identical application of heat to each brass case.

• If you stress relieve your brass for longevity only, not accuracy, you can do it well enough without a case annealing machine, but if you want consistent neck tension for accuracy purposes, the annealing machine is the best way to achieve your goal.

• If you want precision in annealing, it can only be done with an inductive annealer. Then each heat treatment is quantitatively identical.

That's all. No voodoo. No need to sacrifice black roosters at midnight in your reloading room. Just simple physics and a bit of common sense.

There is an informative technical paper available here, titled RELEASE OF INTERNAL STRESS IN BRASS TUBING, By Robert J. Anderson and Everett G. Fahlman that covers the subject of strain relief in cartridge brass.