Re: .223 Brass
Cracks in the neck/shoulder region are from over working the brass, not annealing, or the brass has simply met its service life. Excess headspace can lead to rapid overworking, same for too small a neck bushing if you use bushing dies. Excess pressure shows itself at the other end, flattened/cratered primers, ejector marks, case head expansion. I don't anneal .223 I toss it, but I have a very large supply of LC.