No.
you cant upgrade it twice
It means you can upgrade your guns.
disco stick
You get more maximum ammo when you upgrade the gun. The ak74u usually has 20 ammo, and gets 40 when its upgraded.
No, you can't upgrade a gun more than once.
Makes your gun stronger, makes your maximum ammo more, can add an underbarrel.
it should
you upgrade the ammo by pack a punching your weapon it should costs $5000 to pack a punch which will upgrade your weapon and ammunition
Black Ops 2 Zombies is harder but also way funner than Black Ops Zombies.
You have to beat story mode.After you do that go to the zombies menu and five should be there.
on youtube look at the vids they should tell you