When they first were talking about the 7.62x51 ICSR, I knew someone had been smoking crack and wasn’t familiar with weapons or Infantry MTO&E, or lessons-learned over the past 130 years.
Then they switched to the 6.8 NGSW and stuck with a x51 based cartridge with .473” case head, which is a non-starter for most dismounts in the squad and platoon.
We’ve been needing a true intermediate cartridge solution for at least DMs and LMGs for ages, with the biggest missed opportunity being the .276 Pedersen in the 1930s, followed by WWII and the 1950s service rifle development that doubled-down on .30 Caliber.
One of the things that emerged in all of this was a discussion about cost. The biggest cost is actually ammunition shipping weight, where billions are spent in moving pallets from manufacturing centers to distribution hubs, then to ASPs or deploying or deployed units, then down to the Battalions, Companies, and Platoons.
6.8x51 makes that worse across the force since it’s obviously a lot heavier and bulkier than 5.56.