Virtually all of the Rangers dispatched to Somalia in 1993 were armed with the M16A2, a development of the Vietnam era M16A1, which itself replaced the earlier and much heavier M14.
In 1986 the U.S. Army adopted the M16A2 which had various improvements including a heavier barrel and a larger magazine capacity of 30 rounds of 5.56mm Nato standard ammunition.
In addition all M16A2s can mount the under-barrel 40mm grenade launcher (M203).
K&C's Ranger is aiming his M16A2 w/ M203 slightly upwards as he prepares to launch a grenade round at the enemy.