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.