Sanders should be asked if he knows who Brian Terry was.
Sanders should be asked how the Bolsheviks (his apparent heroes) would have successfully overthrown their government if they didn't have guns. How did Marx envision the 'workers revolution' happening, if they workers didn't have weapons for their revolution?
The Bolsheviks did have guns, of course, but after seizing power they confiscated the guns of the rest of the populace - just like Bernie is advocating, and just like all dictatorships do.