and selected M9 pistols and M16 rifles. The Army is pursuing a two-phase PIP to keep the M4 carbine inventory strong. Phase I upgrades the Army’s M4s to the Special Forces’ M4A1, while Phase ...

Like its predecessor, the M16, the M4A1 operates on a gas-operated system with direct impingement, offering both advantages and certain drawbacks. The M4A1 weighs about 6 pounds without a magazine ...

The M4A1, like its predecessor the M16, is based on a gas-operated system with direct impingement, which provides both advantages and certain drawbacks. The M4A1 weighs about 2.72 kg without a ...