So being in LE I'm always on the lookout for a good tactical rifle and cartridge. Earlier I came across the 6.8 mm REM SPC. Most of the reviews I've read look promising. But, I figured I would get some first hand (or second hand) opinions on the cartridge. Has anyone shot this round from an AR platform? If so, what did you think of the round vs, lets say the standard 5.56 mm? Any help would be much appreciated.