Can this rifle replace the us army’s M4 5.56mm ? True Velocity came out with a revolutionary NGSW 6.8mm 30% lighter weight cartridge. The Next Generation Squad Weapon program has three firearms manufactures competing to replace the legacy small arms. Word on the street is the army will select a winner by sometime around December of 2021 at the earliest. General Dynamics created this gun to replace the M16 which has been around now for over five decades.