Bachman Pawn and Guns on Northwest Highway sold 65 guns that were later seized from Mexican drug cartels, placing the store No. 8 on the newspaper's list, the Post reported as part of a yearlong investigation on guns.
In a brief phone interview, Bachman's owner, Shaun Nelms, faulted the Post's findings and said his store mainly sells to other dealers.
"We're a wholesaler," he said.
The Post said authorities traced the origin of 60,000 guns recovered in Mexico to 7,500 gun dealers in the United States. Texas topped the list.
Tom Crowley, a Dallas-based agent with the Bureau of Alcohol, Tobacco, Firearms and Explosives, said the smuggling of guns into Mexico has become a priority.
Just a few months ago, Gregorio Morales of Lewisville was arrested on suspicion of smuggling weapons into Mexico.
Agents said he worked with an Oklahoma narcotics officer, Francisco Reyes, who pleaded guilty in U.S. District Court in Oklahoma City to recruiting "straw buyers" to purchase weapons for the cartels.
In the Fort Worth-area in 2008, ATF agents arrested seven members of the violent La Familia drug cartel. They were charged with buying high-powered weapons and hiding them in a warehouse in Cleburne. Six pleaded guilty, and the seventh was convicted.
In Fort Worth, the owner of Cheaper Than Dirt gun store said he suspects straw buyers come in almost weekly.
"They're not putting it on momma's Visa card," DeWayne Irwin said. "They're coming in, they've got cash in hand."
He said they often want the biggest and most expensive guns and don't haggle over the price.
"These guys come in with 10s and 20s," Irwin said. "You know it's drug money. Any adult with common sense knows what it is. So we scoot them out the door and try to discourage them from coming back."
At a military base in Mexico City, soldiers have destroyed 90,000 guns seized from the cartels in the past four years, and experts say that's just a fraction of the weapons still out there.
More: The Hidden Life of Guns at the Washington Post