Hi, I was interested in knowing some reasons why 5.56 has become the dedicated and common round instead of the more effective and penetrating 6.8 round? I was looking for ammunition for the 6.8 online and it seems to be very scarce. I was watching on the future weapons show that the guy was saying the 6.8 would be better defense gun for both CQB and mid range combat than the 5.56, but hasn't caught on. What are people's opinions? Has anyone here ditched there 5.56 and gone the 6.8 route? I see there are some nice 6.8 ARs, but lack of ammo is the reason why I decided not to go with this caliber.