Nicole training in the use of the M4 carbine. The M4 carbine is an assault rifle developed in the United States during the 1980s. It is a shortened version of the M16 assault rifle. The M4 carbine and its variants are extensively used by both conventional forces and special forces for Close Quarters Combat (CQC). The carbine's compact size makes it highly effective and maneuverable in confined spaces like buildings and vehicles, which is crucial for CQC situations. The M4 is extensively used by