Hagins had been dealing drugs for years, was an ex-felon with a history of psychiatric problems; he could not buy guns himself. The customer, David Downs, had a nasty crack habit and had been laid off from a Bensalem belt factory.

Downs told a jury at the federal courthouse in Philadelphia that Hagins spotted the sticker on his truck and asked him if he could help him get some guns in Pennsylvania - where they're far easier to buy than in New Jersey.

"I told him yes," Downs testified last month.

By the time the feds caught up to them, Downs had ferried about 50 guns from Bucks County shops to Hagins, who moved many of them to Trenton's pushers and gang members.

Hagins and Downs' transactions were emblematic of a thriving illegal economy: exploiting Pennsylvania's relatively weak gun laws to export firearms.

"Everyone knows where these guns are ending up," said Jersey City Mayor Jerramiah Healy. "You're ending up with 15- and 16-year-old kids having guns."

These types of transactions - buying guns for others, or "straw purchases" - are illegal. They can happen anywhere. But in Pennsylvania, they're exceptionally easy.

Someone with a clean record can often buy a gun in a half hour. It takes weeks, even months, in New Jersey or New York.

As a result, at least for supplying the Northeast, Pennsylvania rivals gun-friendly Southern states like Virginia or Georgia as a firearms exporter, according to data from the federal Bureau of Alcohol, Tobacco, Firearms and Explosives.

Each year, hundreds of guns seized from criminals in New York and New Jersey are traced back to Pennsylvania gun stores, the ATF statistics show.

In 2006, ATF traced 332 guns from New Jersey crimes back to Pennsylvania gun dealers. No other state sent more.

The same year, 461 Pennsylvania guns were seized in New York City and state. Only Virginia sent more crime guns there, ATF found.

A review of dozens of court cases shows there is a seemingly endless supply of people willing to meet the demand for black-market guns. Most are not high-end smugglers but crack addicts, girlfriends of felons, or low-level hustlers looking to make a fast $100.