Administrative Results go through the paces with the XM177, the compact CAR-15 which saw action in many parts of the world before the M4 was introduced as the main service rifle in the U.S. Armed Forces... "The XM177 is the beginning of a long line of CAR-15s that would eventually go on to become the M4 Carbine. The XM177 and its variants first say use in Vietnam, and would go onto many conflicts and be used by a wide host of nations and operators."