I recommend googling "cartridge head stamps" or go directly to "cartridgecollectors.org/headstampcodes.htm" Literally hundreds of alpha/numeric codes and points of origin. Your PMC is some of the best brass I've found from Eldorado Cartridge Corp., Colorado, but made in various places not in the U.S. CBC is also decidedly heavier/thicker walls (.38 spl) made in Brazil.