This is a standard NRA mantra that zero support in reliable data (save those cooked by NRA cooks). The National Crime Victimization Surveys collects information from a representative sample of US population, asking whether Rs were victims of a by crime 9whther reported to the police or not), and if so, about various circumstances of that victimization, including protective measures used by the victim.
The results are quite instructive. The most frequent form of response was "resistance or capturing the offender" (24.5%) followed by "running away" (14%) "getting help" (12%) or "persuading offender" (11%). By contrast less than 1(one) percent (0.8% to be exact) attacked the offender with a weapon (not necessarily a gun) - see http://www.ojp.usdoj.gov/bjs/abstract/cvus/weapons.htm Table 70.
By contrast, the same source reports that firearms were used by perpetrators in 7.2% of all violent crimes and 8.6% of all completed violent crimes.
It clear that guns are more of an offensive than a defensive weapon in crime commission. In fact, the use of weapons in self-defense is negligible. It makes perfect sense, when one considers the dynamics of a criminal incident - the victim has little chance to reach, unlock, and use a fire arms when threatened by an armed perpetrator.
It further follows that Bucher is either a bumbling idiot who does not know what US DoJ is publishing, or a liar that ignores US DoJ findings to score a few electoral points with gun nuts. In either case he is unqualified to be a district attorney - in a civilized country, at least. What's next, mafia boss for district justice?
Wojtek