"It's gotta be quick," he said Monday afternoon. "We're extremely busy."
A fear of violence lingered over the community Monday.
Last-minute gun purchases were being made hours before it was announced there would be no charges in the fatal police shooting of teenager Michael Brown.
The grand jury decision, announced by St. Louis County Prosecuting Attorney Bob McCulloch, prompted a smoke-filled standoff between police and protesters.
Many had expected unrest.
The state had pre-emptively declared a state of emergency. Gun sales had surged in recent weeks, rising continually since Brown's shooting had touched off violent standoffs.
Figures supplied by the St. Louis County Police Department showed a spike in concealed-carry permit requests since August, when the unarmed teen was shot and killed in a confrontation with a white police officer.
There have been three times more requests in November than for the same period last year — 708 this month, compared with 233 in November 2013. Since there's no licence requirement for a handgun in Missouri, those statistics don't reflect the full picture of gun purchases.
Which explains why the owner was so busy at Metro Shooting Supplies. His store is in the suburb next door, across from the St. Louis International Airport.
"We've sold several hundred guns in the last few weeks," owner Steven King said. "People think the city is going to have a lot of problems with rioting and looting."
King said sales are up five times since last year — demand that he believes is being driven entirely by the events in Ferguson.
To illustrate that fear, King tells the story of one customer.
He says the mother of an eight-year-old girl came in to buy her first gun. Until this month, she'd only been to shooting ranges but had never purchased her own weapon.
"She said, 'If something were to happen to (my daughter) I could never live with myself,'" King said.
Mom wound up spending US$862 at the gun shop.
She left with a Smith & Wesson 9-mm handgun, a storage safe, and a pack of hollow-point bullets.
King said most people don't worry about regular protesters. What concerns them, he said, are "splinter groups" — individuals who might use crowds as cover to steal. The fear crosses ethnic lines, he said, explaining that his new customers come from different races, ages and backgrounds.
Events in Ferguson, however, have laid bare racial divides in the country.
That much was evident in a jarring conversation this weekend between ex-New York mayor Rudolph Giuliani and Michael Eric Dyson, a sociology professor at Georgetown University.
It devolved into a near-shouting match, with the host of NBC's "Meet the Press" failing to get a word in edgewise.
Giuliani expressed annoyance that so much attention was being paid to a single shooting by a white police officer — when, he said, people should be focusing on the 93 per cent of blacks murdered in the U.S., being killed by other blacks.
He said African-Americans should be talking about making their own communities safer, so that they don't require such a heavy police presence.
Shouting past the moderator at his African-American co-panellist, Giuliani said: "White police officers won't be there if you weren't killing each other."
Dyson shot back that black people do worry about community violence. In fact, he said, they talk about it all the time. He accused Giuliani of muddying the police-brutality problem with a false comparison and suggested his statements dripped with the logic of "white supremacy."
Meanwhile, President Barack Obama was on another channel, appearing on a different Sunday talk show.
Obama did what he's often done throughout his presidency, whenever racial incidents occur: he attempted to navigate gingerly between the positions espoused by Giuliani and Dyson.
It was like a one-man debating society, bouncing back and forth between point and counterpoint.
Sometimes, Obama said, black-community concerns about policing are justified. On the other hand, he said, sometimes they're not. He said minorities live in more dangerous neighbourhoods and do want a police presence. On the other hand, he said, they want police to be properly trained so that they can distinguish between a "gangbanger" and a non-threat.
He described experiencing discrimination as a young man. He said white people — or, in Obama's more careful wording, "folks on the other side of it" — might not be sensitive to how racial profiling feels.
On the other hand, Obama said, it's important not to overreact.
"My own experience tells me that race relations continue to improve," Obama said in an interview on ABC's "This Week."
"Just in our lifetimes ... there’s no way to say that somehow race relations are worse now than they were 10 years ago, 20 years ago or 50 years ago. Part of what happens is that they get a lot more attention today. Occasionally, problems that used to be pretty common 20 or 30 years ago weren't videotaped.
"Now, you know, somebody's got a camera, and people see it."
He delivered a similar nuanced message after the grand jury announcement Monday night.
Obama said that despite anger, America is a nation of laws and people must remain peaceful. He also said there's work to do on bridging the racial divide, although great progress has been made in just a few decades.
There was also a report of one death from one of these newly purchased guns.
Police were investigating what one media report described as an accidental shooting last Friday, linked to Ferguson fears. Citing police sources, CNN reported Monday that a St. Louis woman was killed with a gunshot wound to the head last week.
It said her boyfriend told police the gun had been purchased out of fear of unrest, and during a traffic accident it went off in the car.