"They didn't announce it officially, but the rumour is that they were going to raise the excise tax on it 500 per cent. It's 11 (per cent) now and that puts it out in the market for $400 a box. It would go up to $2000 if the excise goes up to 500 per cent," he says. Eric Payne, 22, who is in the military, is buying up boxes of 45mm and 9mm ammunition for target practice. "Everybody's buying it right now, probably because of politics, because they think gun laws are going to change," he says. Some put the shortages down to America's two wars, which are causing manufacturers to focus on military need, coupled with increased training exercises by other law enforcement officials. But Mr Gilronan says there is also evidence of stockpiling by private gun owners, who fear the new political climate. "Every time you tell people there's a chance they can't have it, they are going to buy it as fast as they can get it," he says. Rick from Virginia, a tall, athletic-looking man in his mid-30s  he declines to give his last name  has loaded up a trolley with about a dozen boxes of ammunition of various calibres.

"The numbers I have seen suggest that 17 per cent of gun owners in America will defend their right to own guns with their lives," he says. "In order to able to do that, they have to be able to shoot them and so they are buying enough ammunition now so that should there be a shortage or legislation or anything else to restrict the supply of ammunition, they will have everything they need." Asked how many guns he owns, he laughs. "There was a group at one stall back there wearing the same T-shirt. It said: 'If you know how many guns you have you do not have enough'. Let's put it this way: I would run out of fingers and toes." By now, I have attracted a small crowd and another, older man in a cap that identifies him as a Vietnam veteran, hearing that I am a reporter from Australia, looms into my personal space. "Do you know anything about firearms?" he asks. "I have a lot of experience dealing with the press on this and I have yet to see the press do a decent job because I know what your agenda is. "Will you give me your home address so that I can send my friends to get you and your editor if you do your usual 60 Minutes strangle-job?" he says angrily.

I hazard another seemingly innocuous question: "I've heard people are worried about President Obama tightening up on gun ownership, is that right?" "Oh yeah, we are paranoid ex-military, right-wing excrements, can't you tell?" says the veteran, getting more worked up. "Have you read President Obama's lips? Are you familiar with his record as a senator from Illinois?" In the election campaign, candidate Obama declared that he did not believe assault weapons should be available to private citizens and he would look at reinstating the ban that ended in 2004 due to a sunset clause. Legislators have not seriously attempted to reinstate the ban, despite several mass shootings in the US involving semi-automatic weapons. But two weeks ago, when the flow of military-style guns from the US over the border to the Mexican drug gangs threatened to become a diplomatic issue with Mexico, Mr Obama was asked whether he still believed that assault weapons should be banned.

He does, but he added that "none of us are under any illusions" that reinstating the ban will be easy. In other words, it is in the too-hard basket. But that didn't placate the shoppers at the Virginia gun show. A huge number of automatic and semi-automatic weapons are on sale and trade seems to be brisk. I stop to admire what appears to be an M16. "That one," explains the vendor, who declines to give his name, "will fire 600 rounds a minute." It is not allowed to be sold on the spot because it requires a special licence and background checks with the Alcohol, Tobacco and Firearms administration and the FBI. But a few stalls further down, I could pick up, for instance, a very nice semi-automatic such as an M1 carbine, used by the US military, for between $US1000 and $US2000 depending on the model, provided I am a resident of Virginia and I don't have a criminal record. I do not require a gun licence and computers are set up around the hall for instant background checks. Loading

At the next stall down, Dale Blenkenship of Dales Guns tells me the SIG Sauer semi-automatic pistol I am admiring will cost $US350, but he's disappointed when he hears I am from over the border in Maryland, because he can't sell to me. Russell, who also doesn't want to give his last name, says sales are booming because "we don't want it to happen here like your government screwed up your country, taking your guns and freedom away from you".