Originally Posted by fishwater
Thank you for the replies.
That was my first thought, that I messed up the bullet seating, and they might have been crimped a bit. It was scary, because EVERY SINGLE BULLET was coming out cracked.
The cases were all trimmed to length before being loaded, and were all within spec.
Also, the cartridge is already over COAL spec. I could seat them out a bit further but they are right in the middle, in between the recommended, and absolute max length right now. That bullet is just really long!
Remember, once I took these remaining bullets apart, the brass was incredibly hard/brittle.
I am in the process of getting new brass, and will be paying very close attention to the loading process, especially the lubing and neck/shoulder resizing part.
I really appreciate all the help.
You are on the right track to better reloads and not over working your brass . It's not all your fault as I am fairly certain the brass was very hard and poor quality when you got it . If you do use expander ball type dies then annealing is also a good idea after say 3 reloads in your case .
I still say get someone to make a body die out of a 30-378 Full length sizing die and it will solve a lot of issues . Also don't size all the way to the shoulder as this will take some stress off the expander ball as it comes back through .
Brass works well when it's the right hardness for the job harder at the base softer at the shoulder and mouth but if it's too hard where it needs to be soft then things can change rapidly . As hardness increases the grain structure changes and the brass looses it's ability to stretch without fracture .
Get a piece of thin brass plate and cut it in two , bend one piece back and forth until it fatigues and breaks . Then bend the other one once and anneal it with a blow torch then when cool bend it again and so on , it will go on and on not breaking .