Randy Cotter, general manager for Gat Guns, said gun sales at his East Dundee shop have increased 10 percent since June 12, when a man entered a gay dance club in Florida and killed 49 people.

"While the shooting has impact, so does the election, the current state of Congress. That all plays into it," he said.

As Cotter was noticing this increase in sales, lawmakers that represent Fox Valley communities in Washington, D.C., were debating laws that seek to restrict how guns are sold and who can buy them.

U.S. Rep. Bill Foster, D-Naperville, was among the House Democrats participating in a 26-hour sit-in and called on Congress to pass legislation to address gun violence. The demonstration was an effort to push Republicans to call two votes – one on background checks and another on blocking people on the government's "no fly" list from buying firearms.

"As a scientist, I always look at the facts, and gun violence is a public health crisis. It is time we act to stop it," Foster said in statement.

"You don't have to be a scientist to know that universal background checks are a fundamentally good idea. And you don't have to be a scientist to understand that anyone who belongs on the no-fly list should not be able to purchase firearms," Foster said.

The protest was broadcast live on social media and carried by C-SPAN. Across the country, millions of people tuned in to live feeds provided by broadcasts from the smartphones of Democrats—a violation of House rules. Cameras are not permitted to operate when the House is not in session.

After more than 15 hours of speeches by protesting Members of Congress, Speaker Paul Ryan adjourned the House -- over the loud objections of Democrats.

It's the second time in as many weeks that Democrats have taken dramatic action to push their Republican colleagues to hold a vote on measures to expand gun background checks and ban people on federal terror watch lists from buying firearms. U.S. Sen. Chris Murphy, D-Conn., led a near 15-hour filibuster the previous week to force Republicans in the Senate to agree to hold a vote. The proposals failed to get the votes needed to move forward.

U.S. Rep. Randy Hultgren, a Republican who represents Kane and Kendall counties, said in a statement on Facebook he agrees with legislators across the aisle that more thorough background checks, including checks that include terrorist watch lists, are necessary. But he disagrees with a proposal pushed by Democrats that would let the government block many gun sales to known or suspected terrorists.

Instead, he backs a Republican-led proposal that would only let the government deny a gun sale to a known or suspected terrorist if prosecutors convince a judge within three days that the buyer was involved in terrorism.

Both amendments failed to pass a Senate vote.

Hultgren said a judge, rather than "unelected bureaucrats at the Justice Department" should have the final say in barring a suspected terrorist from buying a firearm, according to the statement.

"The burden of proof on denying constitutional rights should lie with the government and go through a judge," the statement read.

Democrats point to public opinion polls that show overwhelming support for expanding background checks on gun sales and banning people on watch lists, including the no-fly list, from buying firearms.

"We have had enough. I'm tired of seeing children who are sitting in their living rooms or bedrooms killed by bullets coming through the windows and walls of their homes. It is absolutely horrific," said U.S. Rep. Tammy Duckworth, D-Hoffman Estates. Duckworth is a candidate for U.S. Senate, challenging the re-election of incumbent Republican U.S. Sen. Mark Kirk.

Kirk bucked his party on gun control earlier this month as four separate Senate measures failed to advance in the aftermath of the nightclub massacre. Kirk and U.S. Sen. Dick Durbin, D-Ill., cast identical votes to support Democratic measures and reject GOP-authored language.

Roger Krahl, owner of R Guns, said his Carpentersville store also has seen an increase in sales in recent weeks.

"What happens is we see a surge in the things government wants to take," Krahl said. "It's sort of like Prohibition. It's only creating an environment where people fear of guns being taken away."

Suzanne Baker of the Naperville Sun, Mike Danahey of The Courier-News, Sarah Freishtat of The Beacon-News and Tribune Content Agency contributed. Megan Horstead is a freelance reporter.

Photography by Scott Strazzantte