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The 10mm round has a colorful, if not distinguished, history in law enforcement having been developed in the early 1980s by the legendary Jeff Cooper and adopted by the Federal Bureau of Investigation as a step up from the standard issue 9mm round. It had been determined that the 9mm lacked the sufficient stopping power needed by agents in the field, and the obvious replacement, the military-issue .45 ACP Colt Government Model or Combat Commander, were deemed too much gun for most agents to carry undercover on a routine basis. Thus, Cooper’s 10mm became the intermediate step.

At least that was the plan, but the high-velocity round proved as hard to handle as a .45 ACP. In 1990, the .40 S&W became the go-to cartridge for the FBI and law enforcement, relegating the 10mm to near orphan status. Today, SWAT, hostage-rescue units, special response teams and some military spec ops elements are the cartridge’s primary users. Oddly enough, 10mm also found popularity among handgun hunters, and the round has seen a resurgence in recent years with gunmakers offering more 10mm models.

On Point

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The new Glock 40 Gen4 In MOS Configuration fills an interesting niche in the law enforcement and handgun hunting categories, where increased accuracy and firepower are essential. With its Modular Optic System (MOS) configuration, the pistols is capable of increasing accuracy for tactical use, hunting and competitive shooting, thus making the G40 a real triple threat.

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To say that the G40 Gen4 In MOS Configuration is twice the gun of Glock’s original 10mm pistol, the G20, introduced in 1990, would be a bit of an overstatement, but not much. The G20 was a service-model Glock with a slightly longer 4.6-inch barrel put into limited use by law enforcement. Glock also recognized the handgun hunting aspect and offered it with a longer 6-inch hunting barrel.

In 1996, Glock added the subcompact G29 and upgraded both its10mm models to the SF (short frame) version in 2009. In 2012, the G29 was among the Glock models re-introduced in the Gen4 series. Now the company has come full circle with the addition of the 6-inch barrel (actually 6.02 inches) for the G40 Gen4 in MOS Configuration.

Optic Ready

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With an overall length of 9.49 inches, the new model offers an unprecedented 8-inch sight radius with the standard white-dot front sight and the wide, U-shaped rear sight. The MOS system gives the gun a removable rear slide plate and four interchangeable mounting bases to seat a variety of mini red-dot optics just ahead of the rear sight. Each mounting base contains the top edges of the slide serrations so they have a fully integrated appearance, rather than looking like something added on top of the slide. The use of recessed mounting bases lowers the optics so they are more in line with the bore. Custom builders call it a “melt” treatment for concealed carry.

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Along with a recalibrated trigger, this pistol has all of Glock’s internal and external Gen4 upgrades, including interchangeable backstrap panels with added beavertails and a dual recoil spring assembly to help diminish felt recoil. The pistol’s capacity is 15+1, and its weight is 28.15 ounces unloaded. Finally, Glock the cold-hammer-forged barrel uses polygonal rifling to ensure a more precise bullet-to-barrel fit, allowing the shooter to attain the maximum velocity and accuracy potential from 10mm rounds.

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