SU-16 refers to a series of semi-automatic rifles and carbines manufactured by Kel-Tec CNC Industries, Inc. of Cocoa, Florida, referred to in Kel-Tec's marketing as "Sport Utility rifles". The SU-16 series is notable for its compact, lightweight and simple design; and for being able to be broken down and folded into a compact configuration for transportation and storage. While the barrel, bolt-carrier and mechanism are steel, the SU-16's stock, receiver, and forend are manufactured of high-strength polymer plastic.
All variants of the SU-16 are chambered in 5.56x45mm, and are capable of using standard M16 STANAG compatible magazines (where not prohibited by state or local law). The SU-16 features a 1:9" twist rifling. The SU-16 incorporates design features derived from several different weapons. It uses the locking bolt design of the M-16, and an operating system similar to that of the AK-47, in which a gas piston drives an operating rod, which is part of the bolt carrier and which rides on a spring contained in a gas tube mounted above the barrel. This design incorporates the operating rod and gas tube into the bolt carrier, allowing them to be removed easily for maintenance and cleaning. As with the AK-47, Armalite AR-18 and AR-180, and compared to the M-16, this design allows for the folding feature of the SU-16 and reduces the amount of propellant residue fouling that accumulates in the chamber and on the bolt carrier. The charging and bolt release handle is located on the right side and reciprocates with the weapon's bolt, allowing it to be used as a forward assist. All versions of the SU-16 incorporate a top-mounted Picatinny rail. In all versions except the short-barreled "D" model, the fore-end opens up to serve as an integrated folding bipod. The SU-16 breaks down into its collapsed configuration with the removal of a single pin, which can be pushed out with a round, and can be broken down for maintenance and cleaning without the use of tools. The bolt-carrier group and receiver constitute the only two assemblies of the weapon.