Lee Loader

Early 45 Colt brass was the so called "balloon head" and was/is not appropriate for modern loading although I understand it survived into the smokeless era in the Colt and also the 45/70 as I recall, probably others. If you find any of those cases put them on the shelf as a memento of a bygone era.

Stay well, Be safe, Make smoke,

Composition, manufacturing processes, storage, and usage all impact brass quality and longevity. So do the cost control considerations of ammunition and component manufacturers. Consider that recycled metal is used to produce the majority of brass feed stock.