Where does the Glock 20 stand today, 30 years after its introduction? Here's What You Need to Know: While not an ideal solution in tactical and urban scenarios, the Glock 20 has earned a sizable following as a reliable hunting and survival handgun. In a catalog saturated with popular 9mm offerings, the 10mm Glock 20 Gen4 stands apart as the Austrian gun manufacturer’s most powerful semi-automatic pistol. The Glock 20 is also the oldest 10mm in continuous production, successfully blending Glock’s legendary reliability with a newfound focus on stopping power. Glock made its initial splash in the U.S. handgun market with the Glock 17, which fast became a bestseller in the early 1980’s for its lightweight, modular, and ergonomically friendly design. Market trends sharply changed, however, with the infamous Miami shootout 1986. It took eight FBI agents armed with 9mm guns a total of 18 gunshot wounds to incapacitate only two suspects, armed with a 12-gauge pump shotgun and semi-automatic rifle respectively; two agents were killed, and five more wounded in the protracted firefight. The FBI and other law enforcement agencies concluded that .38 special and 9mm guns lack the penetration necessary to reliably incapacitate targets. 10mm cartridge-based weapons quickly emerged as a leading alternative; traveling at supersonic speeds and hitting with a muzzle energy of up to 750 pounds, the 10mm round destroys soft tissue and disrupts the nervous system far more efficiently than its 9mm counterpart.