Adam Maxwell was one of the quickest shooters in the first leg of the competition, smoothly firing off his shotgun and AR-15 rifle at a string of targets in 11 seconds.

The gunshots came heavy and sharp in the split seconds before the bullets pierced the dirt berm.

As he finished and walked back, a member of the shooting team told him he had two FTNs — failures to neutralize — a euphemism for the power of the AR-15 to inflict deadly wounds. In his haste, Maxwell shot some of the targets only once, instead of twice. His penalty: 10 seconds added to his time.

Such events, known as 3-gun competitions, have become popular in Minnesota and across the country. Contestants take turns shooting a handgun, shotgun and rifle — usually the semiautomatic AR-15 — at a variety of themed targets, competing to be the quickest and most accurate. The Wednesday night practices in Forest Lake, where Maxwell is one of the best shooters, are low-pressure affairs, but he's traveled as far as Utah, Texas and Idaho to compete for large cash prizes.

The AR-15 that figures so prominently in these competitions has become one of the most feared and denounced weapons in the country, often the weapon of choice among those bent on slaughter.

An AR-15 was used to kill 26 people, most of them small children, at a Newtown, Conn., elementary school, and 14 people in an ISIL-inspired attack in San Bernardino, Calif.

Last Sunday, another ISIL sympathizer killed 49 people at an Orlando gay nightclub with a similar high-capacity semi-automatic rifle, the Sig Sauer MCX. That prompted renewed calls by President Obama and Democratic presidential front-runner Hillary Clinton to ban semiautomatic assault rifles. Clinton derided the AR-15 as a weapon of war with no place in civilian life.

'They don't understand'

But the rifle is still embraced with defiant fervor among recreational firearms enthusiasts in Minnesota and elsewhere who insist that only the perpetrators of such crimes can be demonized, not the weapons. And sporting events featuring semi-automatic rifles continued last week even as the nation mourned its worst-ever mass killing by one person, one made possible by a semi-automatic rifle.

"I think a lot of the fear comes from something [people] don't understand," said Maxwell. "They don't understand that there is a sport that revolves around shooting. They just know that [the AR-15] looks scary on TV."

Mark Stevens, a promoter at the Forest Lake club who also travels nationally for 3-gun events, doesn't agree with opponents of the AR-15 but understands why there's a debate.

"It doesn't mean I don't want to hear what they have to say," he added. "I think it would be very arrogant for me to assume I have all the answers."

The AR-15 rifle was modified for civilian use from the standard rifle used by American soldiers in the Vietnam War. The civilian-use version isn't fully automatic, instead releasing one round for each trigger squeeze. But since there is no need to reload until a full magazine has been used, it still allows for a high rate of fire. Many shooters use magazines that hold 30 rounds.

For an inexperienced shooter, the AR-15 becomes increasingly difficult to fire with accuracy the faster the trigger is pulled. A reporter who shot a dozen rounds at the Forest Lake club hit a cardboard target with the initial shots, but missed high, by as much as 6 feet, when pulling the trigger faster.

Maxwell, who has competed semiprofessionally, said it takes a lot of practice to shoot such rifles quickly and on target.

"You actually have to be an enthusiast and an athlete who really wants to develop this skill to really get good at it," said Maxwell.

The skill and experience level at Wednesday's competition, held at the Forest Lake Sportsmen's Club, varied widely, with one newcomer taking 29 seconds to complete the first part of the competition.

In the second, contestants advanced while intermittently turning to shoot at targets stationed between rows of orange fencing plastic, then firing at another row of targets at the end. One contestant accidentally went past a line of fencing without shooting, losing valuable seconds when he had to back up to fire again.

Participants knew each tenth of a second counted.

"Next stage!" yelled one contestant, walking quickly to the next shooting area.

Pivot and fire again

For the final segment, contestants used shotguns to fire at a half dozen metal targets that sent clay pigeons sailing through the air, forcing them to quickly swivel their barrels upward for a second shot. Afterward, they turned in the opposite direction and raced to a wood table that held two large drainage pipes. They grabbed their AR-15s and shot the rifles through the large cylinders at targets 75 yards ahead, then ducked to the ground to hit much lower targets through the space below the table.

About 20 minutes in, Stevens strapped on his kneepads and took his turn. He missed a few of the clay pigeons. When he had to drop to the ground by the drainage pipes for the final few shots, he leaned back awkwardly on one knee while keeping his other leg straight forward on the dirt.

He cracked jokes about it afterward, admitting, "It just wasn't smooth."

But there was no pressure that night, unlike the coming major Nordic/Vortex Tri-Gun competition at the same venue.

Finally, someone called Maxwell's name — he was the final shooter of the evening. He leaned against a utility vehicle to strap on his kneepads, then pointed his AR-15 at the target, checking to make sure that his scope was illuminated. He dropped to his stomach on the ground near the drain pipes, practicing how he would zero in on the lower targets. He rushed through the sequence, and a friend told him his score — 52.82 seconds — not his best time, he acknowledged, but he'd take it.

Maxwell works as a salesman at Arnzen Arms in Eden Prairie. He said that while business usually slows in the summer, it stays steady during election years. A few people have come in since the Orlando shooting to buy AR-15s, worried about the possibility of a ban.

"If Hillary Clinton gets elected, our store will be … out of stock," he said.

Maya Rao • 651-925-5043

Tony Kennedy contributed to this report