Perhaps emboldened by its headway in protests against the old Colosimo's Gun Center, an interfaith group rallied yesterday against a new target - the Shooter Shop in Kensington.

This time, though, the demonstrators ran into an opposing force: a contingent of pro-gun counterprotesters.

It all added up to a lively demonstration of the First Amendment and a quarrel over the Second Amendment as the sides each mustered about 40 protesters outside the gun shop, on Allegheny Avenue.

When the antigun advocates from Heeding God's Call went into silent prayer, the pro-gun folks sang "God Bless America." When the antigun folks sang a hymn, an opponent shouted, "Long live the Second Amendment."

The Rev. Fred Kauffman, a Mennonite pastor and leader of Heeding God's Call, told his faithful that gun dealers such as the Shooter Shop could do much more to make sure they are "not feeding the illegal gun market."

Kauffman and his band are urging gun shops to sign a 10-point pledge calling for shops to be more vigilant in spotting "straw purchasers" who buy guns in bulk for resale to criminals.

To buttress its case, Heeding God's Call cited a 2004 study that identified the 120 gun dealers in America - out of 80,000 registered sellers - that had each sold at least 200 guns traced to crimes.

With 208 traces, the Shooter Shop made its way onto the bottom of this list.

Yesterday, a man barred a reporter from entering the shop to speak to the staff, saying, "I've been told not to let you in."

An attorney for the business, Dan Del Collo, who was at the protest, dismissed the 2004 study as unreliable. For one thing, he said, it drew on data that were a decade old or more.

Del Collo also said a large number of traces could merely reflect sales volume, not reckless sales practices.

For much of last year, Heeding God's Call protested twice weekly outside Colosimo's, on Spring Garden Street. In the fall, the shop went out of business after more than 40 years, shuttering as part of a plea agreement after federal prosecutors charged it with selling weapons to gun traffickers.

Along with the demonstrators of both stripes, the sidewalk in front of the Shooter Shop yesterday was also crowded with about 10 members of the Philadelphia Police Civil Affairs Unit. Officers kept busy videotaping and photographing the protesters.

The on-scene commander, Lt. Joseph O'Brien, said the surveillance was routine, undertaken by the unit for "every protest" in the city. In case of a crime or violence, the images could help police sort out what happened, he said.

Among other steps, Heeding God's Call wants gun shops to agree to take videos of all purchasers and keep them for at least six months.

However, Dan Roberts, who drove to Philadelphia from Williamstown in South Jersey to protest the God's Call protest, said it was enough that gun merchants abided by the law.

"It's not a gun-dealer problem," Roberts said. "It's a criminal-justice problem."

Asked about that, Kauffman replied that tougher law enforcement had a role in quelling gun crime.

"There's some truth to that," he said. At the same time, he added, "there has to be a way to interrupt the violence" before cases end up in court.

Contact staff writer Craig McCoy at 215-854-4821 or cmccoy@phillynews.com.