The 10mm round has long been a favorite of mine. Its value as a self-defense and duty round is substantial when loaded to its original design specifications. Fired from a revolver in its most stout offerings, it may be one of the best handgun hunting cartridges around. Even in less-powerful loadings it provides significant advantages over the .40 caliber in semi-automatic pistols, remaining one of the flattest shooting semi-auto cartridges available.
As for the downside, recoil is sharp and can be significant. It tends to beat up your pistol and or your hand when loaded hot. Most pistols built to handle it are large and difficult to control—particularly for those with small hands. Ammunition is costly, and anything but plentiful. Even so, a great deal of thought went into its development, with input from some of the best.
In its original form the 10mm was very powerful. Designed with some input from Jeff Cooper starting in the early 1980’s, it was intended to be the perfect autopistol cartridge for self-defense. It mimicked the .41 Mag revolver cartridge and bridged the gap between the 9mm and .45 ACP for autopistols. Given the state of ammunition at the time, both had some issues—and the 10mm addressed them.