Forum Discussion
RunItHorizon
5 months agoRising Rookie
Update:
My friend ran another test. After unlocking the M4A1, he played exclusively with that weapon in multiplayer. After 5 and a half hours, he went from level 0 to level 25. At that point, he hadn't even gotten a suppressor attachment.
In the most criticized COD21, five hours is sufficient to unlock a weapon's full attachments and all skins—including those for Zombies.