Analysis of information sources in references of the Wikipedia article "XM7突擊步槍" in Chinese language version.
The intermediate caliber 6.8mm cartridge falls between the 5.56mm, which is in the M4 and the M249 Squad Automatic Weapon, and the 7.62mm round in the M240 machine gun.
The intermediate caliber 6.8mm cartridge falls between the 5.56mm, which is in the M4 and the M249 Squad Automatic Weapon, and the 7.62mm round in the M240 machine gun.