GRAY, Maine — So many gun dealers called the FBI’s National Instant Criminal Background Check System, or NICS, on Black Friday that the system went down twice and was slowed for those who did get through, Maine gun dealers said Monday.

Even with the glitches, a record number of guns were sold on Black Friday all across the country, Stephen G. Fischer Jr., director of the FBI’s Criminal Justice Information Services Division, said Monday.

“We had an awful time getting through all day, and sometimes we couldn’t get through,” Adam Copp, president of Howell’s Guns & Archery Center in Gray, said Monday. “I don’t know what the problem was. They set a record last Black Friday, so I figured it had something to do with that.”

Those who want to purchase a gun in the U.S. must fill out and sign FBI paperwork. The gun dealer then calls NICS to see if the buyer is barred by federal law from possessing firearms.

“We had people waiting and some said, ‘I can’t wait all day,’ and left,” Copp said. “We may have lost of couple of sales, but we got everything through by Saturday morning. It was the busiest day we’ve had all fall.”

The West Gray Road store sold more than 15 guns, he said.

Customers at Van Raymond Outfitters in Brewer also had to wait on Black Friday. The store lost half a dozen customers because the system was down or the wait was too long, manager Rick Lozier said Monday.

“Sometimes it would take 10 minutes to get though and sometimes it was 20,” the longtime Brewer store manager said. “It was pretty much all day long. We still had a good day considering the holdups.”

Those who left emptyhanded did so “from frustration from waiting,” Lozier said. “Overall, we’re not a patient society.”

The NICS outages that occurred on Black Friday were due to exceptionally high call volumes, Fischer said.

“NICS experienced its highest number of transactions processed since system inception on [Nov. 30, 1998], with 154,873, which is nearly 20 percent over the 129,166 processed on Black Friday 2011,” the FBI official said. “The call centers experienced two short outages on Friday — one for 14 minutes and one for 18 minutes.”

He said, “there is no way to speculate, nor would we, as to how many potential gun buyers got turned away.”

System outages do happen, but they are infrequent, Fischer said.

“NICS has achieved an availability of 99.92 percent over the past 12 months,” he said.

The NICS is a name-check system that combs available records in the National Crime Information Center, the Interstate Identification Index and the NICS Index to determine if prospective firearm purchasers are disqualified from receiving or possessing firearms, the FBI’s website states.

Messages left at the corporate offices of Cabela’s and Dick’s Sporting Goods to see how the NICS outage affected shoppers at those retail stores were not immediately returned Monday.

Both Copp and Lozier said gun sales have increased since the presidential election earlier this month, based on fears President Barack Obama might try to sign into law new weapons bans.

“A lot of people are worried that he’s going to drive this stuff through because he doesn’t have to worry about the re-election,” Copp said. “That is the big worry.”

Customers in Brewer and Gray, who are worried about the possible bans, are looking for assault weapons and high-capacity handguns, Copp and Lozier said.

“The high-capacity guns, the ARs — the politically concerned assault weapons — spiked up, not hunting guns,” the Brewer gun shop manager said.

Sales are up in Gray for “assault weapons — or black guns, we call them — and high-capacity handguns,” Copp said. “People are worried.”

Copp said his customers on Black Friday and since then are not the same people who hit the malls and big box stores looking for deals.

“They weren’t women shopping for Christmas gifts — they were guys buying guns,” he said. “There were some gifts. We do a good Christmas business, but primarily what we’re selling is handguns and personal protection. That and muzzleloaders, of course. The season opened today.”