DALLAS — The death threats began, James Henry recalled, about an hour after the confrontation. “One of them said, ‘You’re going to wish you had a gun, boy, when I fill you full of holes.’ ”

A 35-year-old former Marine, Henry was fresh from an encounter with an increasingly common phenomenon in North Texas: an Open Carry rally, where advocates gather in public places with semi-automatic rifles.

Henry said he simply wanted to make a video of the Memorial Day demonstration by the small but well-armed crowd. Then tempers rose and some curses flew. He left, and before long, he said, hostile phone calls began rolling in.

Thus far, Henry said last week, no violent action has followed. But he and many others worry about the combination of inflamed passions, heated arguments and loaded weapons.

“You know what’s going to happen,” Henry said. “Sooner or later somebody is going to start shooting. … Someone is going to get killed.”

HOTBED OF THE MOVEMENT

Opponents and advocates agree on one thing: Texas has emerged as the hotbed of the open carry movement. Its adherents stand on street corners and parade in other venues with their rifles and shotguns. One of their intents is to accustom the public to the routine display of firearms – even military-style semi-automatic rifles.

Semi-automatics can be fired rapidly because they load from a multi-round magazine. In Texas, no permit or training is required to own or use them.

Open carry activists say they ensure that their gatherings are safe and civil. Participants are urged to practice gun safety and avoid hostile encounters.

“We’re under a microscope,” the organizer of a recent Tarrant County rally warned those about to march. “Our enemies are watching us.”

But some of their tactics –such as entering stores and restaurants with their rifles on full display – are seen by some as needlessly provocative. “Is that the person you want standing next to you at Target?” said Shannon Watts, founder of Moms Demand Action for Gun Sense in America.

She, too, believes violence could erupt soon. “I think it’s only a matter of time before something horrific happens.”

Open Carry organizers dismiss Watts and her supporters as extremists who fan irrational fears. “They’re dishonest,” said C.J. Grisham, founder of Open Carry Texas. “They’re emotional activists.”

Grisham said his group, now at 18,000 members, has mounted a public relations offensive, encouraging press coverage of its rallies. “We’re trying to get the real story out there,” he said. “We’re just trying to counter the negative perception that we have.”

Open Carry Texas supporter Robert Beverly of Fort Worth echoed the message. “These guys aren’t nuts,” he said. “We’re not loons. We aren’t dummies.”

Yet many open carry jamborees are thick with those who, while not seeking armed conflict on city streets, are ready for it. Beverly, 54, said he has joined a militia, through which he has received tactical and weapons training.

He is concerned, he said, about widespread civil disturbances or extensive societal breakdown. “I want to be able to respond to any incident,” he said.

Another Open Carry member, Mark Thompson of Garland, had similar thoughts. “Say if there’s ever a coup in the United States,” he said. “We would have the means to protect ourselves.”

Others worry about threats that, though smaller in scale, may be no less lethal.

“This is the safest corner in America,” Robert Perez declared as he waved a “Don’t Tread on Me” flag late last month at a rally in Haltom City. He was joined there by a dozen or so armed compatriots. “There’s nobody getting robbed here,” he said.

Perez, a 45-year-old auto mechanic from Arlington, carried an AR-15 semi-automatic rifle on his back. The chamber was empty, but he kept a loaded 30-round magazine attached to this gun. He could squeeze off multiple rounds in a matter of seconds.

READY TO FIRE

“I do have ammo just in case,” he said. “We have a lot of people who take issue with what I’m doing.”

Firing on attackers, Perez said, might be his only option. The doleful roll of American mass murder sites — Sandy Hook, Aurora, Virginia Tech, Columbine – often is invoked in the debate over semi-automatic weapons. Gun control advocates use them as rallying points. A semi-automatic rifle was used in the Connecticut school shootings in which 20 children were killed.