ANNEALING UNDER THE MICROSCOPE...some of us do load rifle or bottle neck casings. Some interesting info can be seen here...
https://www.ampannealing.com/articles/40/annealing-under-the-microscope/ (https://www.ampannealing.com/articles/40/annealing-under-the-microscope/)
Very informative read.
It is interesting. I haven't annealed in 30+ years since I shoot mainly pistol now, with some 5.56 and .308 now and then, but I use factory ammo when I do. What I found very interesting was the different annealing programs they had to run, dependant not just on the manufacturer but the run of brass.
Annealing has a purpose to soften the neck area of the brass to help prevent splits or for further case work to be done. The science behind annealing is interesting.
Sometime back I was sent some cartridges that had bullets set back, these were REMAN 10mm in PPU brass. After I tried resizing and taking measurements I found that the cases were spring back open and not holding their resized dimensions. So I did a quick and dirty annealing over the stove to soften the brass some. Afterwards the brass showed signs of maintaining the resized dimensions which held the bullets tighter in the casings.
Having seen where guys are washing their brass and seeing them post the pink color brass, leads me to believe that the brass was being attacked chemically. To me this is not a good practice.
Brass is an alloy and it can vary in its compositions. The more we reuse the brass, the processes can work harden the metal.