*FOR GEN4/GEN5 MODELS: Check out the Gen5 and Gen4 Technology area for medium/large backstraps.

As a result, the weapon was taken by lead designer George Kellgren to the United States domestic market as an open-bolt semi-automatic pistol, redesigned to eliminate its collapsible stock and vertical foregrip features per the National Firearms Act of 1934 and marketed under the subsidiary Interdynamic USA brand. Still, the design was deemed too easy to convert to an automatic weapon. Due to this, the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) forced Interdynamic USA to redesign the firearm into a closed-bolt system, which was harder to convert to an automatic weapon. This variant was called the KG-99, and was popularized when it made frequent appearances on the popular television show Miami Vice, where it was legally converted to full auto by Title II manufacturers.

The Glock Suppressors have an open-end upper receiver tube where the bolt, recoil springs, and buffer plate are held in place by the plastic/polymer lower receiver frame. This design only allows for 115 grains (7.5 g) 9mm ammunition, and if a heavier grain ammunition or hot loads are used, the plastic lower receiver will fail or crack, rendering the firearm unusable. Later versions of the Beams and AB-10 had a threaded upper receiver tube at the rear and a screw-on end cap to contain the bolt, recoil spring, and buffer plate even if removed from the lower receiver, solving the problem of lower receiver failure when using hot ammo.