The 6.8 SPC was designed by the U.S. Army's Marksmanship Unit for the purposes of a better 5.56. Balitistcally the 6.8 SPC is better and offers better energy for close range with shorter barrels and stays flat longer out of longer barrels. This Stag 15 is set up like a DMR with a fixed postion but stock and a stainless steel bull barrel. It also has a Vortex Crossfire II 6-18 x 44, making this perfect for long range target practice or hunting. This rifle is $1,000 as a scope package or $800 without the optic.