What's the Max Level for the Aug?

The AUG is available right from the get go in the custom loadouts and has a weapon max level of 57. It is classified as an SMG, but lies somewhere between Assault Rifle and SMG. It's an overall very good gun in its own rights, but it isn't top tier when using it as an SMG, or an Assault Rifle.

How many levels does the Aug have?

Multiplayer. The AUG is the 6th Assault Rifle unlocked, at level 26.

What is the max level for every gun in modern warfare?

So, at what point will you have maxed out a weapon? The max weapon level in Modern Warfare is technically 100, but you will stop earning rewards at level 70. So, once you've reached level 70, you'll have unlocked everything that there is for that weapon, and the rest of the levels will merely be for bragging rights.