The Kel-Tec KSG is a bullpup 12-gauge pump action shotgun designed by Kel-Tec. It has two tube magazines which the user of the gun can switch between manually. Each tube holds a total of seven 2.75-inch (70 mm) 12-gauge shotshells or six 3-inch (76 mm) shotshells.
The Kel-Tec KSG shotgun is a manually operated, pump (slide) action weapon. Barrel locking is achieved by a swinging wedge, located inside the top of the bolt, which engages the barrel extension. The sliding forend is connected to the bolt by dual operating bars. The ammunition feed is from two independent tubular magazines, located below the barrel.
The user is required to manually select a magazine by switching a three-position lever, located behind the pistol grip. The middle position of the switch blocks the feed from both magazines and allows the user to chamber a single round manually. Switching the lever to one side brings the respective magazine into the feed cycle. Once one magazine is depleted, the user manually switches to the second magazine by pushing the magazine selection lever toward it.
Rounds are loaded into the magazines through a large loading/ejection port, located at the bottom of the gun in the stock, behind the pistol grip. Empty shells are ejected down through the same port. A manual safety is available in the form of the cross-bolt button, located above the grip, making the gun fully ambidextrous in use. Sighting equipment (iron sights and/or red dot sights) can be installed using the standard Picatinny rail located above the barrel. A second Picatinny rail is provided at the bottom of the sliding forend, permitting installation of other Picatinny rail accessories. While not included with the stock weapon, perpendicular forward grips and back-up iron sights (BUIS) are almost always shown in photography and video demonstrations of the Kel-Tec KSG.
The initial release of the KSG had a mixed reception with some having flawless experiences and others having various issues ranging from the selector switch breaking to double feeding. Kel-Tec quickly released a second generation addressing these issues while also offering to upgrade 1st generation KSGs with the second generation improvements for free. Other improvements to the KSG on the 2nd generation include a trigger reset, small shell tube peep holes, and a fix of the action release to be easier to use and ambidextrous.