Back in the 1990s, the US Special Operations Command set out to rewrite the book on combat handguns. The failure of the FBI’s 9mm loadings to stop two homicidal lunatics during the Miami-Dade County shootout was fresh on everyone’s minds. Meanwhile, SOCOM was busy transforming Close Quarters Battle into the rarefied art form it is today. Along the way, somebody decided that we needed a kind of arithmetic mean between a typical combat pistol and a pistol-caliber submachine gun. The result was the Heckler and Koch MK 23.