The raids targeted a neighborhood of Kensington that was virtually a drive through gun market.
175 police and ATF agents descended on the neighborhood Thursday morning, rounding up 22 suspects.
They used an armored personnel carrier and chase dogs to prevent anyone from running off.
"We're not going after rookie criminals," said Mike Campbell from the ATF. "The criminals that we deal with are convicted criminals illegally possessing firearms, and a lot of them would rather shoot at us then look at us if given the opportunity."
The men rounded up Thursday were being processed in federal court, and based on the charges they are facing; it could be a very long time before they walk free again.
Thursday's raid is part of a massive federal and local crackdown on illegal gun trafficking, and investigators say the house on East Atlantic Street in Kensington was the epicenter.
They say undercover agents made dozens of buys there including a laundry list of guns, from small caliber handguns to military assault rifles, 72 guns in all.
In some cases, they didn't even have to get out of their cars to make the transaction.
The agents also raided a number of neighboring houses.
"They blew the door in, they put everybody on the ground, they checked the house, they didn't find anything, and they left. This house had nothing to do with it; they got the wrong house," said a neighboring resident.
The raid is part of the government's surge to fight violent crime in several key cities.
"By these arrests, we can say that these semi-automatic rifles, pistols and shotguns are guns that will never be used against our citizens again," said ATF Agent Sheree Mixell.
The suspects all have previous criminal records and have been in an out of jail.
But the federal charges carry far stiffer jail terms than the state charges they have faced in the past.
"The likelihood fo them being detained is fairly high when compared to the state's system," said U.S. Attorney Zane Memger. "It is a very different experience when you get to the federal system."
The suspects are at least looking at five years in jail.
One of them, Luis Ramos, who lives in that house on East Atlantic Street, is facing charges that could add up to 260 years worth of jail time.