the M16 is unavailable since it's overpowered nature. The only way to aquire the weapon is by glitches.
If you are talking about the M16A4 Assault Rifle, then level 40
you start with it in a default class at level 1.
when you reach level 4
level up
Level 44
It has yet to come out, since the call of duty: black ops hardened prestige edition is not out.
You need to unlock the weapons.
you unlock "five" the pentagon level for zombies. you also unlock the dead ops zombie arcade game.
The AK-47 is unlocked at level 38 , and it costs 2000 cod points.
You unlock it at level 57.
You unlock it after reaching a certain level.
an achievement
Level 22 :)
In Call of Duty 4: Modern Warfare, the M14 rifle is unlocked at Level 46 in multiplayer.
its one of the first things u unlock