http://www.bradycampaign.org/press/related_documents/071603/10worst.asp#3:
"Southern Police Equipment Co. Inc., Richmond, VA. From 1989 through 1996, this dealer sold 447 guns traced to crime; 293 of those guns had a "short time to crime" as defined by ATF. The guns were involved in at least 25 homicides, 32 assaults, 4 robberies, and 386 additional gun crimes. The dealer also sold at least 35 handguns in multiple sales. Ian Ralph Blackstock, a convicted New York drug dealer and the mastermind behind a major gunrunning operation, was sentenced to 25 years in prison for illegally obtaining 115 guns from March 1990 to February 1991 from this dealer and two others through straw sales. Fifteen of those weapons were used in crimes in New York and Washington. In 1999, a handgun was seized from a Richmond juvenile in connection with a drug crime 10 months after being sold by this dealer."
Wow...I've bought guns from them. So have a LOT of Richmond, Chesterfield, and Henrico cops. Same deal with the Virginia State Police. In fact, the shop chose it's location because it's directly across from State Police HQ. This is because it's the biggest gun store in the entire state south of Richmond. Greentops is bigger, but most of that is fishing stuff.
I guess the best way to make the list is to do a lot of volume.
I wonder though...How many guns total did those stores sell? If during the time period in question, they sold 1,000 guns and 500 turned up in crimes, I'd be worried. If they sold 100,000 guns in that same period, and 500 were used in crimes, I'd be much less concerned.