[Glock32]

The original loading of the 10mm from Norma kicked butt. It was great on paper, had recoil close to a .357 mag out of a k-frame and beat up Bren-Tens and Colt Delta Elites like no other.
Todays commercially loaded 10mm Auto ammo only shares the name with the original stuff.

This is from the Dornaus & Dixon 1984 Bren Ten catalog:

The Norma factory loaded 10mm Auto cartridge is a center fire, rimless, brass cased, straight walled, large caliber pistol cartridge. It measures 1.250 inches in overall length with the bullet measuring 10.16 (.40") millimeters in diameter. It uses a special Norma powder designed expressly for optimum muzzle velocity while maintaining safe chamber pressures, and uses a standard .210" diameter large pistol primer. The bullet is a copper alloy full jacket, lead core design, and has a truncated cone shape (Jacketed Truncated Cone or JTC). Bullet weight is 200 granis (13 grams practical). Out of a Norma 5" test barrel (the length of the Bren Ten barrel, full-sized models), muzzle velocity is 1200 feet per second, and produces a moderate average chamber pressure of 37,000 c.u.p. (copper units of pressure). Kinetic energy at the muzzle is 640 foot pounds. Relative Stopping Power on the Hatcher Scale is 72 (30 R.S.P. on the Cooper Short Form). The 10mm Auto moves the striking pendulum farther than the .45 ACP from the same distance, out of the same gun (the Bren Ten shoots both rounds). Because of the unique design of the Bren Ten, the 10mm Auto cartridge has the felt recoil of the .45 ACP 230 grain hardball round out of a Colt Government Model, yet it retains more kinetic energy at 100 yards than the .45 ACP has at the muzzle. The large bullet cross sectional density, along with the velocity and kinetic energy, combine to produce a truly effective cartridge. Ballistically, the closest comparable cartridge to the 10mm Auto is the .41 Magnum. The 10mm Auto cartridge has been designed and developed to be the optimum combat pistol cartridge.