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Ruger AC-556 Select-Fire Automatic Rifle (1980)

Authored By Staff Writer | Last Updated: 2/1/2013

The select-fire Ruger AC-556 became a militarized version of the popular Ruger Mini-14 rifle, a design based on the Vietnam-era M14.

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The Ruger AC-556 was a variant of the popular Ruger "Mini-14" series of semi-automatic carbine rifles introduced in 1973. The Mini-14 itself held origins in the equally-popular M14 gas-operated Battle Rifle of the United States military, this development made possible through a post-World War 2 initiative that sought to replace the war-winning M1 Garand service rifle. As such, the M14 was based on the M1 Garand with the Mini-14, in turn, based on the M14. This then paved the way for the Ruger concern to finalize a militarized form of their civilian-minded Mini-14 offering, the design eventually emerging as the "AC-556". The AC-556 was primarily intended for sale to military and police markets and found a home in a few such groups of the world. Production of the rifle (since discontinued) was handled in-house by Sturm, Ruger & Company, Incorporated of Southport, Connecticut, United States.

The AC-556 retained its gas-operated, semi-automatic features and was chambered for the 5.56x45mm cartridge firing from a 20-round curved detachable box magazine. The system was given a receiver-mounted firing selector which allowed for a conventional single-shot, repeat-fire, semi-automatic fire mode as well as a three-round burst facility and full-automatic fire. Provision was also made for a bayonet mounting at the front of the weapon (near the forward sight) and the barrel was cleared to fire non-lethal rifle grenades for riot control. A flash suppressor was added to the business end of the barrel while a perforated glass-fiber handguard protected the operator's support hand from the generated heat of the barrel during firing. The design was strengthened where possible for the rigors of military service while retaining many of the proven quality features of the Mini-14 before it - including its notable compact profile.

Original AC-556 production versions were marketed with fixed solid wooden stocks. The later AC-556F and AC-556K models brought about use of a folding stock which collapsed under the weapon for a shorter overall length. These latter versions were, therefore, forced to install a full pistol grip under the aft-end of the receiver in the usual way. A thirty-round capacity magazine appeared for AC-556s for a short time.

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Specifications for the
Ruger AC-556
Select-Fire Automatic Rifle


Country of Origin: United States
Manufacturer: Sturm, Ruger & Company - USA
Initial Year of Service: 1980


Overall Length: 984 mm (38.74 in)
Barrel Length: 470.00 mm (18.50 in)
Weight (Empty): 6.37 lb (2.89 kg)


Caliber: 5.56x45mm
Action: Gas-Operated, Rotating Bolt; Select-Fire
Feed: 20- or 30-Round Detachable Box Magazine
Muzzle Velocity: 3,400 ft/sec (1,036 m/sec)
Rate-of-Fire: 750 rounds per minute
Range: 656 ft (200 m; 219 yds)
Sights: Iron front and rear


Variants:
AC-556 - Initial Production Model Designation; solid wood stock.


AC-556F - Folding Stock; pistol grip

AC-556K - Folding Stock; pistol grip


Operators:
United States