As he looked at the store's busy ammunition shelves, he told ABC13, "(Customers are buying) everything. They're buying firearms and ammunition and accessories. We're selling some training and literally everything."
WATCH: Ted Oberg visits Houston-area gun store where shelves are half-empty
Mark, a customer who brought his mom to shoot her brand new handgun at the range, left with five boxes of ammunition. It's the maximum Top Gun allows customers to buy these days. Mark didn't want to offer his last name. He says his ammunition was to replace what he shot at the range, but other buyers he said were "panicked... ammo is one of those commodities that everyone rushes to the store thinking you're not going to be able to have ever again."
Dispelling the rumor, Top Gun's Harrison said his warehouse is "well-stocked. We've been in business 25 years. We've gone through several, several rounds of panic buying unfortunately."
By federal law, the U.S. government does not track the number of guns sold, but it does track the number of background checks for buyers.
Those federal background checks for gun sales in Texas were up 92 percent over the last month, according to FBI data released April 1. Texas saw 274,211 background checks in March compared to 142,928 in February.
Nationwide, data shows there were 3.7 million background checks for gun purchases in March across the U.S. It's the highest number under the background check program ever, dating back to late 1998.
The third week of March, which was around the time states were issuing stay at home orders, set a one-week record for gun background checks in the U.S., according to the FBI's list of Top 10 weeks.
A look at the last five years of background check data shows a similar spike in 2015 during the height of the Hillary Clinton/Donald Trump campaign, when there were 3.3 million checks in one month.
While it appears obvious, the reasons for the surge are hard to pin down among buyers. Phyllis Myer, a first-time gun buyer, was at Top Gun Wednesday afternoon looking for a Smith & Wesson .380. The store sold three before she got there and was out of stock but ordered one for her. Myer said she's wanted a gun for protection for a long time. Asked why she picked today, she blamed procrastination and admitted a little panic.
The National Rifle Association told ABC13 in a statement, "Our nation has seen an uptick in firearm and ammunition sales whenever people feel threatened. We're seeing it now because Americans know that, during times like these, first-responder resources may be limited and their safety is ultimately in their own hands."
Acknowledging the uptick in sales, Kris Brown, the president of Brady United (formerly the Brady Campaign Against Gun Violence), said in a press release, "While it is understandable to seek what can feel like protection in times of upheaval, we must acknowledge the risks that bringing guns into the home pose and take all appropriate measures to mitigate that risk."
At Top Gun all new guns sell with a trigger lock. As has been the case for months, most law enforcement agencies in the Houston area will supply free gun locks to anyone who asks.