Democrats like Senator Joe Manchin (D-WV) and others have made it abundantly clear that no one needs "a 30-round" magazine for a gun.
What, other than crime, could one possibly use a 30-round magazine for?
While there are multiple easy answers to this question, one which is particularly poignant is that such magazines are a regular part of the security Senators like Manchin enjoy in their day to day lives.
Next time you're in DC, look at the security around the buildings in which Manchin spends his time and you'll see armed guards holding MP4s or similar weapons with a 30-round magazine. Guards are using those guns for protection applications.
Of course, the guns and their 30-rounds (or more) are not being used to protect Manchin alone, but also all the other Dem. Senators who have been quick to criticize both the magazines and the guns with which they're identified. Ironically, I have not heard Manchin, or Sens. Dianne Feinstein (D-CA) and Chuck Schumer (D-NY) say they will also ban the "assault weapons" and 30-round mags used in their protection details.
I guess the message to the American people is simple -- Dem. Senators get 30-round magazines while we will be limited to one 10-round magazine and slingshot (or two 5-round magazines and a bow and arrow).