The M16 is fully automatic in the campaign of Black Ops. It is featured in multiple levels in the Campaign, first in "Operation 40," in which it has an ACOG Scope and aGrenade Launcher attached. It is then used in "SOG" with aMasterkey, and other friendly soldiers will carry them with various attachments as well.
The M16 fires in three-round-bursts in multiplayer, like the M16A4. It is part of the default "Assault" class. After having unlocked Create-A-Class, it does not need to be purchased with CODPoints.
The weapon has low recoil and high damage for an assault rifle, meaning it is most effective at medium-long range, especially since its range is higher than any other assault rifle. Its burst-fire mode hinders its effectiveness in close quarters. All three rounds must hit at close-medium range for a kill, and four hits kills at long-range, meaning multiple bursts are usually needed for a kill.
The M16 is overall exactly the same as its previous incarnations as the M16A4, bar its longer range. It is, however, slightly less effective due to the lack of Stopping Power, as more than one burst on target is needed for a long-range kill.