M4 Flat-Top Autoloading Rifle

The Ruger AR-556 M4 Flat-Top Autoloading Rifle, M4-style, direct impingement Modern Sporting Rifle offers consumers an affordable, American-made Modern Sporting Rifle with the rugged reliability they have come to expect from Ruger. Extensively tested during its development, the AR-556 is constructed from top-quality components, including forged 7075-T6 aluminum upper and lower receivers and a cold hammer-forged chrome-moly steel barrel with M4 feed ramp cuts.

Chambered in 5.56 NATO, the AR-556’s carbine-length, flat-top, M4 design is fully configured with a Ruger Rapid Deploy folding rear sight, milled F-height gas block with post front sight, forward assist, dust cover, brass deflector, telescoping six-position stock, improved trigger-reach grip, enlarged trigger guard and one 30-round Magpul PMag. Standardized M4/AR components are utilized throughout, so the AR-556 can be customized easily.

Windage Adjustable Ruger Rapid Deploy Rear Sight: The Ruger Rapid Deploy folding rear sight provides windage adjustability, and is a solid, reliable aiming system when coupled with the elevation adjustable front sight. The rear sight can be folded out of the way to make room for optics but can be instantly redeployed if needed.
Forged 7075-T6 Aluminum Upper Receiver: Made from aerospace-grade 7075-T6 aluminum forging, the flattop upper receiver includes a forward assist, dust cover and brass deflector, and is Type III hard coat anodized for maximum durability.
Shot Peened, 9310 Alloy Steel Bolt: The bolt is machined from 9310 alloy steel and is shot peened and pressure (proof) tested to ensure strength, structural integrity and durability.
Patent Pending Barrel Nut and Delta Ring: The patent pending Barrel Nut and Delta Ring are designed for one person handguard removal and installation. The design accepts standard carbine length handguards. The barrel nut uses a standard wrench and can be swapped with a Mil-Spec barrel nut if desired.
Elevation Adjustable Front Sight: The front sight post is elevation adjustable, and a front sight tool is included. The A-2 Style F-Height allows co-witness with many optics.
Medium Contour Cold Hammer-Forged Barrel: The 16.10 inch medium contour barrel is cold hammer-forged providing ultra-precise rifling for exceptional accuracy, longevity and easy cleaning. The 1:8 twist rate stabilizes bullets from 35 to 77 grains, and the 5.56 NATO chamber allows the use of both 5.56 NATO and .223 Rem. ammunition. M4 feed ramps provide improved operational reliability, and the matte black oxide finish reduces glare and provides corrosion resistance. A Ruger flash suppressor is provided, and the 1/2-28 threaded barrel allows for standard muzzle accessories to be installed.
Single Stage Trigger and Enlarged Trigger Guard: The single stage trigger provides durable and reliable fire control. The enlarged trigger guard is designed to allow for gloved shooting.
Matte Black Oxide Bolt Carrier with Staked Gas Key: The chrome-plated bolt carrier inside diameter and chrome-plated gas key inside diameter provide exceptional resistance to hot gases. The gas key is staked so that it will not loosen after extensive firing. A matte black oxide finish on the exterior of the bolt carrier provides corrosion resistance.
Serrated Face Milled Gas Block: The milled gas block is located at a carbine length (M4) position for improved balance and handling. Multiple attachment points include a QD socket and bayonet lug, for many sling and accessory mounting options. Serrations on the angled face of the gas block provide a low-glare surface.