(TMZ) An official from the D.C. police told a member of the Federal Bureau of Alcohol, Tobacco, Firearms and Explosives that David Gregory COULD display a high capacity magazine on "Meet the Press" Sunday ... TMZ has learned.

Well-placed law enforcement sources tell TMZ ... a staffer from "Meet the Press" called ATF before the show aired to inquire about the legality of David holding the empty magazine during a segment on gun control.  We're told the ATF person contacted the D.C. police to find out if the District of Columbia -- the place where the show is broadcast -- had a law prohibiting such a display.  

Read more: TMZ