Yeah, its illegal... unless you have a Special Deal with the district attorney's office. Then all that matters is if you're a "nice guy" or not. Clearly "nice guy" means loyal DemocRat and VIP in the media.
Legalinsurrection.com's William A. Jacobson wrote: "The short version is that the D.C. Metropolitan Police Department warned NBC News that it could not possess an actual high-capacity magazine, but NBC News went ahead and did it anyway. The MPD recommended a warrant for Gregory's arrest, but that request was nixed by the D.C. Attorney General Irvin Nathan because — my paraphrase — Gregory was just too nice a guy and had no other criminal intent."
The incident occurred Dec. 23, 2012 when Gregory displayed a 30-round magazine for effect while interviewing LaPierre following the Newtown shootings.
In Washington [DC], it is illegal to possess a magazine holding 10 rounds or more, even if empty.
If Wayne LaPierre had held the magazine, they'd most likely have charged him AND perp-walked him out of the studio in cuffs on live TV. Because Wayne LaPierre is not a "nice guy" by those standards.