Ruger AR-556

Overview

The Ruger AR-556 is an American-made, semi-automatic, AR-15-pattern rifle produced by Sturm, Ruger & Co. Introduced in 2014 as Ruger's entry-level direct-impingement AR-15, it was designed to deliver the reliability and modularity of the classic M4/AR-15 platform at an affordable price point. The standard rifle is chambered in 5.56 NATO (which also accepts .223 Remington), feeds from standard STANAG/AR-15 magazines, and ships with a 30-round Magpul PMAG in most states. Over its production run, Ruger expanded the line well beyond the original carbine to include the upgraded MPR (Multi-Purpose Rifle), a free-float-handguard model, and an AR-556 pistol, with chamberings reaching beyond 5.56 into cartridges such as .350 Legend, .450 Bushmaster, and .300 AAC Blackout. It became one of the best-selling budget ARs in the U.S. market and was offered from 2014 until Ruger announced its replacement, the Harrier series, at the end of 2025.

History & Background

Sturm, Ruger & Co. introduced the AR-556 in late 2014 as a no-frills, value-priced AR-15 intended to compete directly in the high-volume "entry-level modern sporting rifle" segment. It joined Ruger's earlier, more expensive piston-driven SR-556 but used a conventional direct-impingement gas system to keep cost and weight down. The standard model proved popular as a first AR for new shooters as well as a budget-friendly platform for training and recreational use.

Ruger steadily broadened the family. The AR-556 MPR (Multi-Purpose Rifle), a more feature-rich rifle with a longer free-float handguard and mid-length gas system, was added in 2017. A free-float-handguard standard model and additional chamberings followed, and in 2019 Ruger released the AR-556 pistol, a short-barreled, brace-equipped variant. On December 31, 2025, Ruger announced the new Harrier rifle as the successor to the AR-556 line.

Design & Features

The AR-556 is a gas-operated, semi-automatic rifle built on the familiar AR-15 layout, with a forged aluminum receiver set and a multi-position telescoping buttstock. The standard model uses direct impingement; the design is otherwise highly conventional and broadly compatible with the AR-15 aftermarket.

• Operating system: Gas-operated, direct impingement, with a rotating bolt. The standard carbine uses a 7 in carbine-length gas system; the MPR uses a 9 in mid-length gas system.
• Receiver: Forged aluminum upper and lower receivers (AR-15 pattern).
• Barrel: Cold hammer-forged 4140 chrome-moly steel with 1:8 in twist rifling. The standard model has a 16.10 in barrel with a birdcage-style flash hider; the bolt is machined from 9310 alloy steel.
• Handguard/furniture (standard): A CAR-15-style handguard, an M4-style six-position collapsible buttstock, and a Ruger-designed pistol grip. The gas block, with an integral front sight post, is a proprietary Ruger design that incorporates a quick-detach sling-swivel socket and a bayonet lug.
• Handguard/furniture (MPR and Free-Float models): A free-float handguard with M-LOK accessory slots and a continuous top Picatinny rail; the MPR adds a radial-port muzzle brake and a Magpul or B5 Systems stock and grip.
• Sights/optics: The standard model includes a fixed front sight post and a Ruger Rapid Deploy folding rear sight; the flat-top upper is drilled for optics mounting on its Picatinny rail.
• Magazine/capacity: Standard 30-round Magpul PMAG (a 10-round aluminum magazine is supplied in states with magazine-capacity limits); accepts standard AR-15/STANAG magazines.

Technical Data

Feature	Specification
Manufacturer	Sturm, Ruger & Co.
Model / Pattern	AR-556 (AR-15 pattern)
Firearm type	Semi-automatic rifle (and pistol variant)
Action	Gas-operated, direct impingement, rotating bolt
Caliber	5.56 NATO / .223 Rem (standard); also .350 Legend, .450 Bushmaster, .300 AAC Blackout in select models
Capacity	30 rounds (10-round magazine in restricted states)
Barrel length	16.10 in (409 mm) standard; 18 in (457 mm) MPR; 10.5 in (267 mm) pistol
Gas system	Carbine-length (standard); mid-length (MPR)
Weight	Approx. 6.5 lb (2.9 kg), standard model
Materials	Forged aluminum receivers; 4140 chrome-moly steel barrel; 9310 alloy steel bolt
Year introduced	2014 (produced 2014–2025)

Variants

• AR-556 (standard): 16.10 in barrel, carbine-length gas system, CAR-15-style handguard, fixed front sight and folding rear sight. 5.56 NATO/.223 Rem.
• AR-556 with Free-Float Handguard: Standard rifle upgraded with a free-float M-LOK handguard; offered in 5.56 NATO/.223 Rem and .300 AAC Blackout, with 30-round and state-compliant 10-round versions.
• AR-556 MPR (Multi-Purpose Rifle): A more feature-rich rifle with a free-float M-LOK handguard, continuous top rail, mid-length gas system, radial-port muzzle brake, and Magpul or B5 Systems furniture. Offered with 16.1 in and 18 in barrels in 5.56 NATO/.223 Rem, plus .450 Bushmaster (18.63 in barrel) and .350 Legend (16.38 in barrel).
• AR-556 Pistol: A 10.5 in-barreled variant with a free-float M-LOK handguard and an SB Tactical SBA3 stabilizing brace; offered in 5.56 NATO and also in .300 AAC Blackout and .350 Legend.

Calibers / Chamberings

• 5.56 NATO / .223 Remington (standard across the line)
• .300 AAC Blackout (Free-Float and Pistol models)
• .350 Legend (MPR and Pistol)
• .450 Bushmaster (MPR)

Intended Use

The AR-556 is a general-purpose modern sporting rifle. The standard carbine is well suited to recreational and range shooting, training, and home defense, and serves as an affordable entry into the AR-15 platform. The MPR's longer barrel, free-float handguard, and mid-length gas system favor more precise target work and 3-gun-style shooting. The big-bore and specialty chamberings (.350 Legend, .450 Bushmaster, .300 Blackout) extend the platform to deer hunting in straight-wall-cartridge states and to suppressed/short-range use, while the AR-556 pistol offers a compact, brace-equipped option.