The National Rifle Association on Sunday offered young children free membership and the opportunity to win a high-powered rifle or shotgun.

A "Youth Day" at the influential gun lobby group's annual convention in Indianapolis was scheduled to culminate with a prize draw in which participants could take home a WBY-X rifle or shotgun supplied by Weatherby, a major firearms manufacturer and a sponsor of the event. All were also given a free six-month youth membership of the NRA.

Media were banned from covering Youth Day. When the Guardian approached the ballroom in which the event was to take place, one of two police officers guarding the room ordered a reporter to leave and said no journalists were even allowed to be in the adjacent 350-yard corridor.

“That is just what the organisers have told me,” the police officer said repeatedly, when asked why media were supposed to be barred from the area, where other convention attendees were walking around freely.

In a reference to this year's host city, the youth event was speedway themed. Children were expected to participate in a so-called "Sponsor's 100", in which they would dash around the exhibit hall in the vast Indiana Convention Center and make "pit stops" at sponsors' booths, where they were to collect corporate handouts and merchandise from weapons manufacturers.

Official corporate backers of Youth Day included major gun manufacturers such as Remington, Smith & Wesson and Marlin, as well as Brownell’s, which claims to be the world’s biggest supplier of firearms accessories and gunsmithing tools.

Back in the youth event ballroom, other challenges were set up for young participants including air-rifle shooting; lassoing, with two men dressed in full cowboy gear; and mocked-up fishing in a paddling pool.

Andy Myers, 38, of Ohio, said his three young children were keenly awaiting the Youth Day activities.

“Oh yeah, these guys are all revved up for it,” Myers said of Cody, 12, Sarah, eight and Wyatt, six, who all wore their own convention lanyards.

“I’ve always been a shooter, and I wanted them to learn safe gun use,” said Myers. Dismissing suggestions his children might be too young for firearms, he said: “For me, it is all about safety. Just as with any other phobia, the younger a person is introduced to something, the better."

“I’d rather my children were introduced to guns by responsible people in a place like this,” Myers went on. “I wouldn’t want them just getting bad ideas off the TV, which can be a bad influence.”

“I’m enjoying it here, but I’m tired after being here the whole weekend,” said Cody, who added that he enjoyed shooting an AK-47 and M-22 at a gun range with his father.

Asked to name his favourite part of the convention, he said “the models” before clarifying: “The girls, not the guns”.

A man shows his daughter a six-shooter at the 143rd NRA Annual Meetings and Exhibitsin Indianapolis. Photograph: Karen Bleier/AFP/Getty Images Photograph: KAREN BLEIER/AFP/Getty Images

The NRA describes Weatherby’s WBY-X range of rifles and shotguns as adding “edgy, attention-grabbing, dipped finishes” to some the firm’s best-selling guns. The firearms range in price from $549 to $749.

At the Weatherby stand in the exhibit hall, Taylor Nahrgang, a marketing manager for the firm, said the winning child would be expected to "turn over the firearm to a parent or guardian" following the draw. "I believe that's how it's going to work," said Nahrgang.

Bear Pascoe, a tight end who was released by the NFL's New York Giants last year, was signing autographs for Youth Day participants who stopped at the Weatherby stand.

"I think it's important to encourage young people, even those in the cities, to get outdoors and learn how to hunt safely," said Pascoe. "But it's not just about killing – it's also about conservation."

In a statement made when the firm was unveiled as a sponsor of Youth Day, Mike Schwiebert, Weatherby's vice-president of marketing, said: "Weatherby is proud to help support NRA Youth Day and make it a special experience for all the participants."

"We very much appreciate the opportunity to partner with the NRA in providing opportunities for our youth to learn more about our industry and all the fun the outdoors has to offer, whether it's hunting, shooting or rodeoing."