The murder rates, weapons used, and ethnicities of murderers and victims are well documented; see the FBI's own statistics (bjs.gov) for the details.
In summary, most law abiding gun owners in the U.S. don't commit homicide. Among whites, guns are most likely to be used for suicide.
Among blacks, guns are most likely to be used for homicide, and most of their victims are also black. In fact out of about 11,000 gun homicides per year, over 6000 are black-on-black shootings, mostly males 16-39, mostly urban ghetto gang members. Thus, less than 1% of the U.S. population commits over half the gun homicides (Hispanics have the next largest share).
If you control for the unfortunate murder rates in the ghetto areas, actually the per capita gun violence in the U.S. is almost the same as Canada and western Europe, maybe 1% higher but certainly not warranting the kind of stereotyping that inevitably accompanies any discussion about gun crime in America. Except for a few neighborhoods, most American cities today are as safe as, or actually safer than those of Europe.
You can argue with some validity that guns are too easy for gangs to obtain, but that's really separate from what we're talking about here which is lawful carry.