I loaded up some .223 ammo last year, and have been shooting them a couple times, in a couple different rifles. Now, when I look at the empties I'm noticing that most of them have small neck cracks. It's like the brass is brittle or something, but it's just normal brass from my bucket of range pickups, never had a problem before.
It's cheap FMJ bullets and surplus AA2200 powder, a full power load. As I recall, I think I SS tumbled the brass. I'm wondering what I did wrong here.
They shoot fine. I don't care about the brass since 5.56 brass is plentiful and free off the ground at the range. Besides, I just chop the necks off the cracked ones and make .300BO out of them.