Hi Gang, Cartridge brass doesn’t necessarily mean the brass is
made from expended cartridges. Just as most of today’s ‘root
beer’ is not really made from ‘roots’, cartridge brass refers to
the formulation of the brass, the proportion & mix of materials
that go into it.
Cartridge brass is usually defined in industry as S.A.E.
standard 70 A.
SAE stands for Society of Automotive Engineers. It defines &
publishes standards for many items used in industry.
The composition for cartridge brass is:
copper, 68.5 - 71.5%
lead, 0.07% maximum
iron, 0.05% maximum
zinc, remainder (100% minus the sum of the previous 3 metals)