Right as you all know, most people know K/D is the main requirement for ranking up. But you can't start a new account and get 1,000 kills and no downs and get the shotgun rank. You have got to get a certain amount of kills before ranking up.

You're K/D is the main factor of ranking up in CoD: Black Ops 2 Zombies. To find out your K/D you find your CO-OP STATS, no your career stats and you find your co-op stats by going on your name in the lobby, like select your name but don't press A and then go right on the analogue stick and then right again. To find your versus stats go right on the analogue stick again. The reason why you calculate your co-op stats is because when you play grief you may get a lot of downs by jumping on the enemy teams heads or just simply getting downed by Zombies or by the other team and Treyarch has made it so the downs you get in grief do not count towards your rank and they get added to the career stats and versus stats, not the co-op stats.

K/D required:

This K/D is not accurate as it's different for everyone and apparently according to EverythingPiff the K/D requirement gets higher and higher as more people are getting more kills on Zombies so Treyarch are making it harder to rank up.

Skull: 20-60, very easy to get the skull in my opinion, just don't get a lot of downs.

Skull with knife: 80-100+ Yes some people might have got the knife below 80 K/D but they most probably calculated the career stats.

Shotguns - I would say about 180-200+ people use to get it at a K/D of 150 but I've heard people getting it at a higher K/D than 150 but they most probably calculated the wrong K/D as well.

This is just a little information but hope this helps.

Thank you for reading hope i helped