HOUSTON — On one side of an avenue in downtown Houston, people filed into the National Rifle Association’s annual convention this weekend to talk guns, admire guns, buy guns and invoke as holy script the Second Amendment right to bear arms; that is, guns.

On the other side of the avenue, people protested against guns, the defenders of guns, the proliferation of guns and the unholiness of American’s easy access to guns that facilitated two mass murders this month; that is, the killing of 10 people, all of them Black, in a Buffalo supermarket, and the killing of 21 people, 19 of them children, at a Texas elementary school.

The avenue is called the Avenida De Las Americas.

As people on one side of the avenue sweated and shouted in the baking Texas sun, others filed into the comforting cool of the George R. Brown Convention Center. But the air-conditioned hall was not hermetically sealed. The massacre of schoolchildren earlier in the week had been in Uvalde, just 300 miles west of here. In time and distance, it was too close.

Inside, politicians spoke of “hardening” schools to a mix of N.R.A. faithful and newcomers curious about the cause. Outside, veteran and novice protesters waved handmade signs and photographs of children shot to death this week, in faint hope of changing minds.

These protesters included people like Dana Enriquez-Vontoure, an educator for more than 25 years, who stood outside the convention center with a sign she had made hours earlier. It repeated three words five times:

“Buses Not Hearses.”

“It used to be that you would leave your babies with me and they would be safe,” Ms. Enriquez-Vontoure, 46 and the mother of two girls, said. “Now we live in a world where we can’t promise that.”

She scoffed at suggestions by some gun advocates to increase school safety by arming teachers and other school officials. She said the doors at her local schools are locked during the day. To collect her daughters, she has to scan a QR code, fill out a form and wait for her child to be escorted out. No guns involved.

Just then, a criminologist and mother named Aramis Miller appeared by Ms. Enriquez-Vontoure’s side. She was holding a sign of her own — “Do Not Scapegoat the Mentally Ill” — and the two of them were about to join the larger protest, which attracted many hundreds of people, across the avenue from the convention hall. They have known each other since elementary school.

But those who flashed the proper credentials could escape the heat of the furious teachers and baking sun and enter the welcoming cool of the N.R.A. convention.

Here was Michael Shao, 50, Chinese-born and now living on Long Island, who said he was promoting firearms-safety programs for Asian Americans unnerved by the spate of violent attacks against members of their community. And here were three men from Chicago, all wearing the Ukrainian colors of yellow and blue, browsing for binoculars, night-vision goggles and other items that might be useful.

“We’re just looking around,” said Igor Terletsky, 50. “Seeing what is new on the market and how we can support our Ukrainian brothers and sisters.”

And here, too, was a white-haired man wearing a T-shirt that said: “We the People Are Pissed.”

The like-minded inside the convention mingled amicably, their gun-talk bonding interrupted only by the angry, sometimes obscene chants emanating from across the Avenida De Las Americas, and by journalists asking for their reactions.

Tim Hickey, 45, who had come from Cleveland to promote his business, PatchOps.com, which sells “morale-boosting” patches and political T-shirts, rankled at the “You hate kids!” chorus being sung at the moment. He has two children, ages 14 and 12.

“I would right now die for one of their children,” Mr. Hickey, a bearded former Marine, said. “Would they do that? I don’t think so.”

He called the Uvalde massacre “heartbreaking,” and said that many gun owners grieve in a slightly different way than others “because we wish we were there to stop it ourselves.”

Mr. Hickey defended the gun laws in place, repeated a common refrain that “you cannot legislate evil” and saw no connection between the Uvalde shooting and the N.R.A., including this convention.

“That’s the media,” he said. “That’s what you do.”

Standing beside him was Kat Munoz, 34, from Novi, Mich., who described herself as a survivor of domestic violence and a social media “influencer” for female self-defense. Her therapy dog, a Belgian Malinois named Millie, sat at her feet.

Ms. Munoz is a mother of two, ages 11 and 9. She too expressed deep sadness over Uvalde. She also defended the country’s gun laws and the N.R.A. She said as far as she knew, none of those responsible for mass shooting deaths were N.R.A. members. And, she said, “Gun laws don’t change psychopaths from being psychopaths.”

She went off to find a place for Millie to relieve herself, with intentions to stay far from the protesters gathered across the street. Later, while in line to hear former President Donald J. Trump address the convention, Ms. Munoz texted that “recent events” had made her wonder whether “we could compromise with raising the age to buy a firearm or stricter background checks on AR-15s,” the style of weapon used by the 18-year-old gunman in Uvalde, and the 18-year-old accused gunman in Buffalo.

“If that’s what it takes to not get rid of our rights altogether, I would not oppose that if absolutely necessary,” she wrote.

The shooting massacres in Buffalo and Uvalde — which join Pittsburgh, Charleston, Parkland, Sandy Hook and other locations too many to name here — had other effects on the N.R.A.’s celebration of itself this year.

In the cavernous hall outside the convention center’s exhibit area, an electronic sign continued to promote a Saturday night musical event called “NRA’s Grand Ole Night of Freedom,” featuring Lee Greenwood, billed as “America’s most recognized patriot”; Don McLean, of “American Pie” fame; and Larry Gatlin, the country and gospel singer. Tickets: $25.

But all three dropped out late last week. Mr. McLean told Fox News that performing would be “disrespectful.” Mr. Gatlin told CNN that it “would have been kind of a classy move” for the N.R.A. to cancel the convention and instead have a moment of prayer or silence.

There was another noticeable absence at one end of the hall, where, according to the N.R.A.’s map of exhibitors, a large space had been reserved for the Georgia firearms company Daniel Defense, the manufacturer of a gun purchased by the man who killed 19 schoolchildren in Uvalde. Instead, the space was occupied by a few tables and a popcorn machine.

But the many exhibitors who did show up did their best to provide a blissful, if temporary, separation from the realities waiting just outside the doors. There was something for everyone, from the dedicated hunter to the anxious survivalist to those seeking outfits that could fashionably conceal a handgun.

Here were knives and handguns and rifles, artfully displayed and available to be held. At one firearm manufacturer’s booth, a salesman urged a reporter to pick up a short-barrel rifle with a side-folding stock. “Touch it! Feel it!” he said seductively. “It won’t bite.”

Here were hand-held devices to pick up your spent cartridges, sleek vaults to store your guns and promotions for gator hunts. A booth for the N.R.A. cigar club. A booth for a wireless provider promoting Christian conservatism. A long line for some “Silencer Smooth,” or whatever else was brewing at the Black Rifle Coffee Company.

As Friday wore on, N.R.A. members began to leave the convention center’s protective bubble. They knew that the exhibit hall would open early Saturday morning, offering the latest in Kalashnikovs and Rugers and Glocks, and that on Sunday, the convention’s last day, many would gather in the grand ballroom for a breakfast with prayer on the menu.

In the Friday evening heat, some conventioneers lingered on their side of the avenue, smoking cigarettes, watching the protests with disdain, occasionally taking selfies with the angry crowd as a backdrop. Several said they believed these demonstrators had their rights, too.

Others ventured across the two lanes of road, not to engage with the shouted accusations that spared no one, including older veterans, but to collect their cars or make their way to their hotels. They passed placards saying “Enough Is Enough,” and “Guns Are the Death of U.S.” and “Am I Next?” — this one held by a girl barely taller than the crowd-controlling barrier gates, over which were draped children’s clothing stained blood red.

Some of the N.R.A. members, carrying bags of convention swag, smiled and waved as they passed. Others, though, kept their eyes trained on the hot pavement.