Zombies gun level system and fastest way to level up.
If the weapon is locked, The weapon will not progress in Leveling up.If you wanna level up guns faster do not Re Pack-a-Punch your weapon. On maps you can get Deadshot perk do it, headshots Levels you and your gun faster. If you want to level up your character faster Re Pack-a-Punch your gun and get Dead Wire on. It will give you the same XP amount for getting a knife kill so x2-x3 XP per kill you get with the ability, works will with double XP.
Submachine Guns: 1500-/+ Kills to Max out the Gun Level (MAX=Level 13)