The Ruger Mini-14 is a small, lightweight semi-automatic carbine manufactured by the U.S. firearms company Sturm, Ruger & Company, Inc..
Designed by L. James Sullivan and William B. Ruger, the rifle employs an investment cast, heat-treated receiver and a version of the M1 rifle locking mechanism with a self-cleaning, fixed-piston gas system. The Mini-14 product page describes it as a “simple, rugged Garand-style breechbolt locking system, with a fixed-piston gas system and self-cleaning, moving gas cylinder.”
The rifle is available in stainless or blued finish with hardwood, synthetic, or laminated stocks and an 18.5-inch (470 mm) barrel. Target models are currently available only in .223 Remington and are not chambered to fire the 5.56x45mm NATO round. They feature a 22-inch (560 mm) heavy barrel and either a laminated wood or Hogue overmolded synthetic stock. Most Mini-14s have a classic sporter appearance, in contrast to comparable autoloading rifles such as the SKS and AR-15. However Ruger now offers some Mini-14 rifles in a black ATI adjustable folding stock with a pistol grip. While the magazines of the Mini-14 resemble M16-style STANAG magazines, the two designs are not interchangeable.
The Mini-14 and its variants are a common sight in movies for several reasons. Firstly, despite being a semi-automatic-only weapon, it can be easily converted to fully-automatic operation by licensed movie armorers. Secondly, and perhaps more importantly, it is incredibly reliabile with blanks; in the movie armoury business it is known as "The Jamless Wonder", owing to the fact it never jams or stovepipes using movie blank ammunition, even when fired on fully automatic, something that cannot be said of any of the other common 5.56×45mm weapons used in films. As a result of this reliability, it is frequently used as the base rifle when productions seek to construct their own fictional automatic weapons.
Also in Predator 2, one of Peter Keyes men in the OWLF taskforce is seen carrying a pair of distinctive Muzzelite MZ14 Bullpup assault rifles, which are the full-size selective fire Ruger AC556 housed in a third-party bullpup stock.