Hey guys, I found an awesome way of levelling up fast with the drop zone game mode.
Setup:
Perk 1- blind eye
Perk 2- any
Perk 3- any

Primary- any light machine gun (I use mg36)
Also works well with Barrett
Secondary- stinger

Simple enough, wait for enemy to get a care package, shoot the helicopter with stinger for 300xp every time.
As soon as you've trained blindeye up to pro you can destroy any helicopter/kill streak with around 20 bullets from mg36. Straif runs can get you up to 1200xp
The most I've had so far is 40k xp in one game including 5000xp challenge bonus.

Hope this benefits someone as its Lvld me from 40 to 55 in around 45 mins.