LEIGH SALES, PRESENTER: Australia's gun laws, introduced after the Port Arthur massacre in 1996, are set for a significant test.

From next month, an eight-shot shotgun will be available in Australia, under the least restrictive gun category.

It's a powerful weapon that fires and reloads quickly.

Australian gun control groups are outraged. But the importer, the son-in-law of north Queensland MP Bob Katter, says he doesn't get all the fuss.

Dylan Welch was given exclusive access to the gun in its Brisbane warehouse.

GUN OPERATOR: OK. All clear?

VOICE OFF-SCREEN: Clear.

(Gun operator fires off five rounds)

DYLAN WELCH, REPORTER: It can fire eight shots in as many seconds, using a firing mechanism straight from the Wild West.

The gun's going to hit our shores next month. To see it, we went inside this high-security Brisbane compound.

ROBERT NIOA (shaking hands): Dylan.

DYLAN WELCH: Hey, Robert. How are you?

ROBERT NIOA: Yeah, good. Good to see you. Come on through.

DYLAN WELCH: Good. Thanks for having us here.

DYLAN WELCH (voiceover): The owner is Robert Nioa, son-in-law of federal MP Bob Katter, and Australia's biggest gun importer, bringing in about 20,000 guns a year.

(To Robert Nioa) So this is the gun range in here?

ROBERT NIOA: Yeah. So we've got our indoor range here and we've got the guns all ready.

DYLAN WELCH (voiceover): Nioa took us to his private gun range to show the shotgun at work. His company has its own publicity team, which filmed us while we were there.

ROBERT NIOA: So what we're going to do first, Dylan: we're going to fire the Adler lever action shotgun, which has been the subject of some of the discussion this last week or two.

DYLAN WELCH (voiceover): In gun circles, there's much excitement. The Adler uses a century-old firing mechanism, called a lever action, in a modern gun.

(Slow motion footage of gun operator firing rounds)

DYLAN WELCH (voiceover): Nioa's already sold 7,000.

(To Robert Nioa) And over what period did you make all those pre-sales?

ROBERT NIOA: Within a week or two of launching the product to the market.

DYLAN WELCH: That's got to be a good reaction?

ROBERT NIOA: It's a good reaction, yes.

In Australia, if you're wanting to use a shotgun for hunting, it has been difficult to get a gun that has more than two shots, which is safe to use while you're on a motorbike and while you're walking around.

DYLAN WELCH: Concerns about the shotgun surfaced when this video from the gun's Turkish manufacturer was discovered.

(Footage from Adler Hunting Arms Company video, showing gun operator rapidly firing weapon)

SAMANTHA LEE, GUN CONTROL AUSTRALIA: This gun would devastate Australia's gun laws because it's a rapid-fire firearm and gun owners are describing it as a cross between a lever firearm and a pump-action shotgun.

PORT ARTHUR MASSACRE EYEWITNESS (archive): She was waving her arms around and she was saying, "There is a man in the cafeteria who has gone berserk with a gun. He's killing everybody there."

REPORTER (archive): Twenty dead and most of the injured were in this one spot.

JACK JOHNSTON, SUPERINTENDENT, TAS. POLICE (7.30, 2006): Carnage is the simple way to describe it. It's probably the only single word...

DYLAN WELCH: When 35 people were killed by Martin Bryant at Port Arthur in 1996, John Howard ushered in a new era of tighter gun laws.

Today pump-action shotguns are limited to people who hold a category 'C' or 'D' licence: a small and highly restrictive class.

The largest and least restrictive category is 'A' - and that's the category Nioa wants for the Adler.

ROBERT NIOA: That is because the effective range is 50 yards. They are a low-velocity, inaccurate weapon.

PHILIP ALPERS, PROF., FOUNDER, GUNPOLICY.ORG: This gun is categorised as an 'A' category gun, which makes it the easiest to obtain. You have to answer the fewest number of questions, do the fewest number of tests. And the police see a category 'A' gun as a relatively harmless tool of the trade, tool of the farm.

DYLAN WELCH: 7.30 emailed every police force in Australia to ask if they classified the Adler as category 'A'. Most have. But the ACT said it would be banning the gun outright, because it included a magazine that held more than five rounds.

Greens Senator Penny Wright wants the gun restricted to only those shooters with category 'C' or 'D' licences.

PENNY WRIGHT, GREENS SENATOR: The fact is that this weapon is clearly not far off a pump-action shotgun. And we severely restrict the use of those because of the speed with which they can be used. So only professional hunters can use those.

It seems to make sense that a gun which is very similar should have the same kinds of restrictions and not be available to casual, recreational shooters.

If you're a mass shooter, which is what the Port Arthur laws were designed to curb, then that's the type of gun you go for. You go for something that's going to just fire and fire and fire and fire and fire. And people are going to have no defence against it for eight rounds. That is a rapid-fire weapon.

DYLAN WELCH: Robert Nioa says the comparisons with a pump action shotgun are wrong.

(To Robert Nioa) So that's the Adler and that's the pump-action, or that's a lever-action, that's a pump-action. Show me the difference.

ROBERT NIOA: So the traditional lever shotgun: you have to remove your hand from the trigger on every cycle of the gun that you do like that. The pump-action shotgun, on the other hand: you can (uses pump) move a lot more quickly. So there have been claims that this action is the same as that action and it is just simply not true.

DYLAN WELCH: Some users of online gun forums clearly see this as a way of getting around the 1996 gun laws.

FORUM POST 1 (voiceover): Get one before your government catches on.

FORUM POST 2 (voiceover): Somehow someone managed to sneak in lever shotguns with seven plus one capacity.

FORUM POST 3 (voiceover): It is a direct challenge to the restrictive and draconian legislation enacted in Australia.

FORUM POST 4 (voiceover): Wow, I really want one of those now.

ROBERT NIOA: We've got extremist elements on every side of the argument. I can bring up some nutters from Gun Control Australia's website if you like and we can compare notes of extreme views.

PHILIP ALPERS: The problem is that it's like drunk driving. You have to set a threshold and that threshold has to be somewhere.

And what the gun industry is doing is constantly testing that threshold, trying to push through it, trying to get past it. And that's how you create new gun markets.

DYLAN WELCH: Robert Nioa is not just a gun importer. He's also a key member of Australia's gun lobby.

(To Robert Nioa) Isn't it your job to, in some ways, try to argue for the relaxation of laws in some areas; to broaden the scope of what is permissible? That's your job, isn't it?

ROBERT NIOA: No, not necessarily. So on any end of the debate you have extremes. So in the firearms community, we have extremists: there's no question. However, they don't get to the table with government and they don't get taken seriously.

PHILIP ALPERS: There are people out there who are constantly whittling away, trying to make guns easier to come by. And the public needs - from a public health perspective - the public needs to realise that it could be under threat.

LEIGH SALES: Dylan Welch reporting.