There has been some discussion in the past about piston guns being inaccurate or not as accurate as DI guns. I just picked up the September 2009 Guns & Ammo and on page 82 there is a piece written by Patrick Sweeny about the LWRCI M6A2 5.56mm. Paulo, if you feel the need to move this because it's not 6.8 I understand.
He conducted some 100 yard, five shot accuracy tests using a Leupold 3.5x10X scope.
Remington 55 gr FMJ - 1.5"
Federal 69gr Gold Medal Match - .80"
Hornady 60gr Urban - TAP - .75"
Wolf 62gr FMJ - 1.7"
Hornady 75gr TAP-precision - .75"
Fiocchi 69gr Matchking - .80"
Winchester USA 55gr FMJ - 1.2"
Black Hills 75 gr Heavy Match - .75"
The author reported zero stoppages and clean operation.
I know there are some DI guns out there that can shoot more accurately, but for a combat gun this is excellent. In any event, most people can't outshoot their guns anyway. Though this is 5.56 I'm pretty sure a 6.8 version with SSA's 115 grain OTM or 110 grain Pro Hunter would shine in a similar test.