Appears as if they are ditching the 6.5/6.8 rounds and going back to the 7.62 NATO, albeit in a beefed up cartridge…?
"Norman said that the most important new feature would be the significantly increased chamber pressure to ensure that the rounds fired will penetrate all known body armor at a distance of up to over 1,900 feet (600 meters). The aim is to equip the service members in the field with an automatic rifle that fires a bullet at a pressure equivalent to that at which a tank would fire.
The chamber pressure for rifles currently in use is approximately 45KSI (kilopound per square inch), or 45000 PSI. The Army anticipates that the new weapon will have a chamber pressure of 60-80 KSI, which is the chamber pressure exhibited by an M1 Abrams tank."
“The Army previously focused its efforts on developing an improved carbine that still fired rounds between 6.5mm and 6.8mm to supersede the M4, but have now shifted priorities toward a beefy and highly efficient automatic NGSAR.”
“The beefed-up rifle is intended for this purpose and prototypes are currently undergoing testing at Fort Benning in Georgia by the Soldier Lethality Cross-Functional Team. Initially, the weapon will fire the 7.62mm XM11158 Advanced Armor Piercing (ADVAP) round while new specialized rounds are under development.”