Most of our readers know that Colonel Jeff Cooper loved the 1911 and thought that it was and is the best option for those serious about pistolcraft. There are books about both the man and his love for the 1911. However, while Col. Cooper was a devout worshipper of the .45 ACP, he also expressed an interest in a pistol caliber capable of pushing a 200-grain bullet at 1,200 feet per second. And he thought that such a caliber would be ideal for times where we might require a pistol to reach out to 50 yards.

Pursuant to this goal, Col. Cooper played a prominent role in developing and designing the Dornaus and Dixon Bren Ten. He expressed optimism for both the pistol and the caliber, as he felt they brought a new level of ballistic performance to the pistol shooter. The Bren Ten was a CZ 75-based pistol designed around a new and powerful cartridge, the 10mm Auto. The Bren Ten and the 10mm Auto cartridge enjoyed a surge in popularity in the early- to-mid-1980s, but manufacturing and supply problems doomed the pistol and the cartridge, with both on life support.

Then, on the morning of April 11, 1986, eight Miami FBI agents spotted and approached two wanted bank robbers. In the ensuing firefight, Special Agents Dove and Grogan were killed as well as the two bank robbers, Matix and Platt. The event shocked the nation as well as the law enforcement community. The autopsies of the two crooks revealed that the then-issued FBI service round, a 9mm, lacked sufficient penetration to readily incapacitate. Had one round penetrated Platt’s body an inch more, it’s likely that the two FBI agents would have survived the encounter. This real-world event became a driving force behind the 10mm Auto and validated Cooper’s idea that magnum-level ballistics in a semiauto had serious application in the law enforcement world.

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