I anneal my cases when I start to get a differing OAL with a .001" press fit because of hard brass. Annealing is the one area I still have trouble with. The first time I tried it, I simply twirled the brass in the flame until the neck and shoulder turned blue, and dropped it in water. Worked like a charm! But the SECOND time, well... I could never get the brass to anneal the second time. It simply got harder. Strange.
I firmly believe in science over voodoo and I'm sure there must be a perfectly reasonable explanation for this. My guess is it has to do with the grain structure of the brass itself.
Try this experiment: Take a hard case that's never been annealed, and twirl it in the flame until the neck and shoulder turn blue and drop it in water. Then size it and load a bullet and enjoy the wonderful feeling of accomplishment at having annealed your own brass. Next: pull the bullet out and repeat the process just like you did the first time. WHOA! doesn't work, does it?
After a lot of frustration and lost brass I finally decided to simply err on the side of caution and anneal as little as possible on the neck ONLY with a slowly turning electric drill and a big quartz clock sitting behind the flame to keep time. This turned out to be to about six seconds, just enough to discolor the neck down to the very top of the shoulder. After removing from the flame I immediately I direct the drill to a bowl of water to cool the neck and limit heating of the rest of the case. I can anneal over and over like this, and my OAL is consistent because the brass has softened somewhat, but it never is as soft as is was when it was fresh.
I truly would like to understand what is happening here. Does the brass need to be work-hardened to some extent before being annealed again successfully? Does cooling in water somehow preserve the grain structure of the annealed brass? Annealing rifle brass is one subject that still seems to be shrouded in mystery for me. I've picked up some good information at 6mmbenchrest.com, but I feel like that there is still a lot of misinformation going around. Loading one's own ammo is difficult and dangerous enough as it is - perhaps someone could suggest a book that tackles this subject.
Thanks for constructive input.