Standard SR-556 upper chambered in 5.56 mm NATO/.223 features a heavy contour, 16.1″ barrel with a 1:9 twist rate, and is capped with a Mini-14/SR-556 flash suppressor mounted on 1/2-28 threads. A one-piece, ten-inch quad rail handguard provides ample room for mounting sights, optics and accessories. Made exclusively for Ruger, this SR-556-specific handguard is pinned to the upper receiver, creating a near-monolithic upper receiver assembly and providing a rugged mounting system for the piston driven transfer rod.
A carbine-length version of the popular SR-556 two-stage, piston driven AR-style upper is also available. The carbine upper features a heavy contour, fluted barrel that is 1-3/4″ shorter and a half-pound lighter than the barrel on the standard SR-556. The 1:9 twist rate, 16.1″ barrel on the carbine features an integrally machined flash suppressor, which minimizes the overall length of the barrel while complying with ATF regulations for civilian and commercial sales. This carbine version maintains the mid-length gas system and heavy (.850″) barrel contour under the handguard, but the barrel is fluted for weight reduction and to promote barrel cooling.
Those seeking to equip their modern rifle with ample power for hunting medium-sized game or greater muzzle and downrange energy capability for defensive or tactical roles can select an upper chambered in the capable 6.8 SPC caliber. The SR-556/6.8 features upper features a heavy contour, 1:10 twist barrel with a standard SAAMI 6.8 SPC chambering. The chrome-lined, cold hammer-forged barrel is 16.12″ long, is threaded 5/8-24, and is capped with the effective and distinctive Mini-14/SR-556 flash suppressor.All three should be available for purchase at http://www.shopruger.com/ soon.
**UPDATE** MSRP $1449
- Double Aught