The issues with the .223(5.56) is that each bullet just doesnt have enough mass to give decent stopping power. The 7.62, on the other hand, starts falling out of the sky at a couple hundred yards. I am surprised that you were the first I saw to mention the 6.8SPC... From what I’ve seen its one of the best compromises between the .223’s flat trajectory, and the 7.62’s stopping power.
http://www.barrett.net/firearms/rec7
“. The 7.62, on the other hand, starts falling out of the sky at a couple hundred yards.”
Which “7.62”? 7.62 NATO or 7.62x39? The two are completely different and the 7.62 NATO certainly doesn’t fall out of the sky in only a few hundred yards.