Problem is, you can do the annealing wrong and cause issues. I bought some reloaded .223 ammo from a large company. They had annealed the brass as part of the reloading process. Most of the ammo I had did fine, but then the second batch of 1000 had issues. 1st 1000 rounds, I had one case break in half right at the base of the annealing. Thought it was fluke, and moved on. 2nd batch of 1000, is when it really showed up. 1st box from that batch, I opened and fire 16 rounds out of the 50 in the box. Had 6 rounds out of that box broke in half during firing right at the base of the annealing. After speaking to some friends in the industry, and returning all of the ammo I had from the company, I found out that the issue was that the either annealed the cases for to long, or they annealed at to high of a temp which weakened the cases. The last case that was stuck, was in there so bad I had to jam a chamber brush into it and then use a rod from the muzzle end and tap it with a hammer to get it out.
Long story short, don't mess with it unless you know what you are doing with annealing. It's to soften the neck after forming it, but you can soften it to much if you aren't precise about it.
