Your chances of NOT being hit, by me with 10" CAR,
scoped, canned, from the bipod, at 400 yds, are REALLY bad, if you offer me the sort of shot and conditions YOU'D need to hit me at 600 yds with a scoped 308 auto rifle. I"m willing to bet big $ on that. You'd need IDEAL firing conditions to hit me at 600 yds. Give me those same conditions at 400 yds, and the odds are at LEAST 4 to 1 that I'll hit you. Dont kid yourself about the shorty 223 being so "short ranged". The 69 gr hpbt, started at 2500 fps in the 10" barrel, still has 350 ft lbs left out there, same as a5" barreled .45 has at the muzzle, with ball ammo. It's still got 220 ft lbs left at 500 yds, too.
Since you used to claim 2700fps from a 69gr in an 11" barrel there is no way in hell anyone is going to believe you've shot 2500fps 69gr at 400 yards to find out what your lack of abilities really are.
You know what happens when an Iraqi is hit from a short barreled AR beyond the known effective range? He runs off and they find him days later healing up at home. It rarely puts them down for the count.
A highly tuned match AR in proper hands can be a 1/4 MOA gun, but not a damn one of them ever used a gun with junk parts from Model 1 Sales and a 10" barrel. You have no benchrest skills.
If you actually have a silenced 10 inch or 11 inch AR15 with a silencer you made and installed on it you are guilty of mu;tiple violations of the Federal Firearms Act. If you do not, then all your "data* is imaginary. Which is it?