How a Tec-9 works

The Intratec TEC-9, TEC-DC9, or AB-10 is a blowback-operated semi-automatic pistol. It was developed by Intratec, an American subsidiary of the Swedish firearms manufacturer Interdynamic AB. Introduced in 1985, the TEC-9 was made of inexpensive molded polymers and a mixture of stamped and milled steel parts, and the simple design of the gun made it easy to repair and modify. The TEC-9 developed a negative reputation for its association with organized crime and mass shootings in the 1990s. However, it was a commercial success, and over 250,000 copies were produced until Intratec dissolved in 2001.

Interdynamic AB, a Swedish firearms manufacturer based in Stockholm designed the Interdynamic MP-9, intended as an inexpensive 9mm submachine gun based on the Carl Gustav M/45 for military applications. Interdynamic did not find a government buyer, so it was taken to the United States domestic market as an open-bolt semi-automatic pistol, but the design was deemed too easy to convert to fully automatic fire. Due to this, the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) forced Interdynamic to redesign the firearm into a closed-bolt system, which was harder to convert to full automatic. 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 KG-9 and KG-99 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 grain 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 TEC-9 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.

Following the 1989 Cleveland School massacre, the TEC-9 was placed on California's list of banned weapons. To circumvent this, Intratec rebranded a variant of the TEC-9 as a TEC-DC9 from 1990 to 1994 (DC standing for "Designed for California"). The most noticeable external difference between the TEC-9 and the later TEC-DC9 is that rings to hold the sling were moved from the side of the gun with the cocking handle to a removable stamped metal clip in the back of the gun. In 1993, the weapon was the subject of further controversy following its use in the 101 California Street shootings[4][5] That same year, California amended the 1989 Roberti-Roos Assault Weapons Control Act (AWCA), effective January 2000, to ban handguns having features such as barrel shrouds. During the 1990s the TEC-9 also developed a reputation for its use by American street gangs and organized crime syndicates, who were attracted to the large capacity 32-round magazines and cheap cost of the firearm.

The TEC-9 was produced from 1985 until 1994, when the model and TEC-DC9 variants were banned nationally in the United States, among the 19 firearms banned by name in the now-expired 1994 Federal Assault Weapons Ban (AWB).. This ban forced Intratec to cease their manufacture, and forced them to introduce a newer model. The following year Intratec introduced the AB-10, a TEC-9 Mini without a threaded muzzle/barrel shroud and sold with a smaller 10-round magazine instead of 20- or 32-round magazines. However, the AB-10 still accepted the larger capacity magazines of the pre-ban TEC-9 models, and were often acquired by users in place of the standard magazine. In 1999, the AB-10 was notoriously used by Dylan Klebold, one of the perpetrators of Columbine High School massacre.

In 2001, the Supreme Court of California ruled that Intratec was not liable for the 1993 101 California Street attacks, and that same year Intratec was dissolved and production of the AB-10 model ceased. Although still found on the used firearms market and nationally legal since 2004, the TEC-9 and similar variants are banned, often by name, in several US states including California, New York, New Jersey, and Maryland.