Gun and weapon enthusiasts packed the Tanner Gun Show so tightly this weekend, some aisles were impossible to walk down.

Background checks are taking around two weeks because of the tremendous backlog in Colorado from sudden, overwhelming gun demand, but vendors at the show at the Denver Merchandise Mart said Saturday they had never seen the event so busy.

“It’s pandemonium,” said Ron McDuffee of McDuffee Arms.

Although he had expected the show to be busy following vast media coverage of gun-related stories, McDuffee said he was still “surprised by the level of demand” for assault-style rifles.

The show, which ran until 5 p.m. Saturday and runs again from 9 a.m. to 4 p.m. Sunday, advertises on its website that it is “working hard to provide same-day background checks to allow for faster purchase.”

As of 2:20 p.m. Saturday, the Colorado Bureau of Investigation had 12,406 checks in the queue, which McDuffee estimated at a two-week wait time.

“For something that usually takes minutes, never more than a few hours,” he said.

As of 7 p.m., Saturday, CBI listed 12,797 checks in queue with a wait time of seven days. CBI listed 1,643 checks as processed on Saturday. The CBI has asked lawmakers for $500,000 to help handle the backlog.

Craig Billado of Berthoud said that while waiting that long for the check was irritating, he believed others understood the importance of process.

“It’s like waiting in line at the DMV,” Billado said. “No one likes it, but you just have to do it.”

If a patron bought a firearm at the show, they could either meet the licensed firearm dealer at their shop or another gun show once the background check cleared, or have the dealer mail the gun to another licensed dealer’s shop, run another check and pick it up there, show officials said.

The demand for assault-style rifles increased the weapons’ value exponentially, and rifles that were going for $1,000 a year ago are going for $3,000 today, Billado said.

John Adams of Pasternack’s Pawn Shop said show customers had been understanding of the extended background-check wait times.

“It’s part of the program,” he said. “People are being very patient.”

The show was not without protesters, who held signs as cars made their way into the Merchandise Mart parking lot.

Karen Woods of Parker was holding a sign condemning assault-style rifles and wearing a large photograph of her granddaughter around her neck.

Woods said her birthday gift to her granddaughter, Natalie, who turned 7 Saturday, was protesting at the show in the name of the 20 children, about Natalie’s age, who were murdered Dec. 14 at Sandy Hook Elementary School in Newtown, Conn.

Too many people who should not have access to guns are slipping through cracks in the system, Woods said.

“You can’t run a background check on crazy,” she said.

Ryan Parker: 303-954-2409, rparker@denverpost.com or twitter.com/ryanparkerdp