The 10mm Auto and .40 S&W share an intimate history, with the 10mm Auto being the parent cartridge of the .40 S&W. But do they share even more than that? In this week's video, we look at how the 10mm Auto cartridge came to be, and consider the truth behind some of the differences between the two cartridges. Watch this week's video to learn more about the history of the 10mm Auto.