Is 5.56 not enough for you? Well the Ruger version of the AR-15, the SR-556, is now available in 6.8mm SPC. The SR-556/6.8 features a heavy contour barrel with a 1:10 twist and comes with a 25 and 5 round magazine. The SR-556/6.8 MSRP’s at $1995.00. Check it out at Ruger.com.