Ckevin, just keep on kill n those zombies! I am sitting here reading all the post and headache people go through for shotties. I mean I actually got a friend who started a whole new account and lost everything he worked for the past 6 years for shotties. Just rock transit and they will come...
You want shotguns rank? The easiest way is to play solo, solo is easy to get to the high rounds beause you have no lag, less zombies, no one that gets in your way. I have a friend who likes to play solo and he has the shotgun rank. I like to play with friends but it's almost impossible to get the shotgun rank when you play zombies with others. I have the skull with knife.
I imagine you are pretty close to getting them with those stats.
If you really want them badly, I advise you to make a committment, and play one (or two) solo games every day, where you make it to at least level 40, without using the revive perk.
If you do this for a week, you should end up with at least 17,500 kills and only 7 downs, which will raise your KDR to 237. I would be very surprised if you didn't receive shotguns by the end of the week.