The M16A2 carbine features a shorter 14.5-inch XM4 barrel, making it more maneuverable than the standard M16A2 rifle, which has a 20-inch barrel. This design provided a balance between the portability of a carbine and the performance of a full-sized rifle.
The M16A2 carbine retained key improvements of the M16A2, such as a heavier barrel for increased durability, an adjustable rear sight for enhanced accuracy. But different with the M16A2 rifle, the M16A2 carbine change its 3 burst firing mode to the full-auto firing mode to improve firepower.