6.8 may outperform 5.56 ballistically but that is the only area it outperforms.
6.8 may outperform 5.56 ballistically but that is the only area it outperforms. Tombs said "a step up in every sense" but that just isn't the case. "Every sense" implies every aspect of the cartridge; the truth is that 6.8 only outperforms ballistically. The part that he overlooked was the cost and less-common, more expensive parts & components for the gun and reloading... 300 BLK fills that void quite nicely with the added benefit that I can run supersonic ammo and switch to heavy subs that are whisper quiet using my suppressor just by switching mags... that CANNOT be done with 6.8... RE: parts & components of 300 BLK, it uses the very, very common 30 cal bullets that are already out there and the brass is converted from 5.56 brass... performance of the 300 BLK rivals that of 6.8 in close. Out at further distance it can still be effective if the shooter does his part. 300 BLK isn't the perfect cartridge just like 6.8 isn't perfect either. This isn't a caliber debate. I like the 300 BLK because it is the PERFECT cartridge for what I want and 6.8 does nothing for me over 5.56.
Overall, cost of getting set up for, and reloading for 6.8 will be well above that of 300 BLK and that is a huge factor. After-all, for people that shoot a lot, the cost of the gun pales in comparison to the cost of the ammo that will be run through it.