How are zombies rankings calculated in Call of Duty: Black Ops 2?

I’m quite a fan of Black Ops zombies especially Black Ops 2, and I have currently Rank 4, skull with knife, and I was wondering why I haven’t got to rank 5 yet.

I used to get taken down a lot in the early games but now with more experience I tend to only go down maybe once/twice per game with 1k kills.

The way I see it, my options are:

• Somehow reset all my stats and start over (by deleting save, etc.)
• Create a new account (not something I want to do)
• Keep grinding (it is even possible at this stage? tips?)

A lot of people suggest to calculate kill/death(down?) ratio, although others say this is not the major player in the rank “algorithm”.

My question is how much of a grind I would have to do with the below stats, and if there is any better way to get to shotgun rank in BO2 zombies? I never reached a very high round (40+) so I kinda think it could be related to that.

• Kills: 263988
• Downs: 2529
• Deaths: 1426

Links:

• Ranking System Explained & How To Rank Up
• What KD do you have to have in zombies in order to get shotguns?