10mm is honestly my favorite pistol cartridge. I sadly don't have one right now, but I did have a former FBI issued Smith and Wesson 1076, which was one of the best 10mm pistols available up until recently. In the early 90s the FBI adopted the 10mm Auto cartridge as their official sidearm cartridge, replacing the .38 Special and 9mm. They did this after the events of the 1986 Miami Shootout, where two bank robbers armed with a shotgun and a Ruger Mini-14 rifle got into a firefight with eight FBI agents who were mostly armed with .38s, 9mms, two .357 Magnums, and two Remington 870 shotguns. One of the agents had his .357 on the car seat next to him and lost it when he had to break quickly, so had to rely on his snub-nosed .38 backup pistol. The other agent with a .357 actually had his pistol loaded with +P .38s, which aren't as potent as actual .357 Magnum rounds. Only one agent came away unscathed, but it took several rounds each to stop the robbers (12 for one and 6 for the other) and most of the shots were not instantly fatal or incapacitating. They were able to continue to engage the agents for four minutes until one was struck in the back, then above the right eye and chest after he turned around which took him out of the fight, and the other was shot three times in the face.
The FBI decided their agents needed better firepower. They adopted the 10mm and approached Smith and Wesson to build them a gun for the relatively new and uncommon round. Smith and Wesson built the gun on their Gen 3 semi-auto design, but had Wayne Novak help them out. S&W and Novak basically custom designed the pistol for the FBI, changing many of the features found on their other Gen 3 pistols (including their other 10mm offerings) in the process. It was a traditional DA/SA action, single stack pistol, but instead of the typical slide-mounted decock/safety lever found on other Smiths, they instead moved the decocker down on the left side of the frame, much like those found on SIG Sauer pistols. The hammer was bobbed and Novak tritium sights were mounted.
The problem was that most FBI agents at the time didn't have a lot of firearms experience before they entered the academy. The older agents were used to their .38s and 9mms, and the newer agents weren't used to shooting period. They had a difficult time coping with the stout recoil of the 10mm (about 700 ft. lbs. at the muzzle at the time). So they worked with their ammunition supplier Federal to develop a lighter load. They settled on a 180gr hollow point traveling at 1000 ft./sec. vs. 1300 ft./sec. for the original loading. So now they had this big, single stack auto with neutered ammo. Eventually Smith and Wesson figured they could take that same load data but cut the cartridge case down so it would fit in a double stack auto, and that's how the .40 S&W was born.
Why do I bring this all up? Well, because the FBI adopted a special light load for their duty ammo, the rest of the manufacturers making 10mm ammo followed suit, and for the longest time all factory 10mm ammo was loaded lighter. It's a similar story today, but more ammunition manufacturers are starting to load 10mm back to it's full potential. Buffalo Bore and Double Tap have some pretty awesome loads that are actually more potent than the old standard loads (800+ ft. lbs. in some cases). So if you're going to get into 10mm, make sure you check the load specs. I'm personally of the opinion that if you're going to buy a 10mm pistol, but only buy ammo loaded to 1000 ft./sec. and just over 500 ft. lbs. at the muzzle, you may as well stick with .40 Short and Wimpy.
I'll eventually get myself another 10mm pistol. I really like the SIG P220 Legion in 10mm, but the one I'm really interested in is the new FK Brno pistol with the polymer frame and caliber swap ability. The pistol comes with three barrels: 9mm, 10mm, and their proprietary 7.5 FK. I was really looking forward to Vltor bringing back the Bren Ten pistol, but they abandoned the project and no one has taken them up on their offer to sell off the tooling and R&D data. I was really excited about the Bren Ten getting a second chance. Tangfoglio/EAA Witness make some nice 10mms too.
