Special measures are being put in place to deal with the "higher number" of guns that will be brought into Britain for the London Olympics, Heathrow officials said.
A Heathrow document about preparations as host airport for the Games quoted by the Press Association reads: "All passengers will travel through the normal customs procedures when arriving at Heathrow.
"We do however expect a higher number of firearms to come through the airport due to the shooting events."
The Olympics will have 390 athletes bringing 780 firearms and the Paralympics will have 140 athletes with 20 firearms.
They are headed for the shooting competition venue at the Royal Artillery Barracks on the edge of Woolwich Common in south-east London.
The document adds: "When the competitors arrive, firearms will be collected and transported by approved handler to airside Locog (the London 2012 organisers) vehicles where they will be secured and subsequently transported to the Royal Artillery Barracks (RAB).
"On the day of issue of firearms to athletes, UKBA (the UK Border Agency) will perform necessary checks against required paperwork within the armoury at RAB."
It was also revealed that Heathrow is preparing or its busiest-ever day on 13 August, the day after the Olympic closing ceremony.
Workers at the UK's largest airport will have to deal with 35% more departing baggage than on a normal day, according to Heathrow forecasts. This is around 203,000 items up from 150,000.
Executives are expecting a 45% jump in departing passengers on this day, to around 138,000 from 95,000, in comparison to a normal day.
The same increases are also forecast for the numbers of arriving passengers on July 26, the day before the Olympic opening ceremony.
BAA, which owns six UK airports including Heathrow, expects its net costs surrounding London 2012 to top £20 million in order to manage the extra demand and challenges of the Games at Heathrow.
Above: the Olympic stadium. (Press Association)
Athletes will get their own dedicated Games terminal which is set to open on 13-15 August. It is being geared up for use by 10,100 departing athletes and to offer bag collection from the Olympic and Paralympic Village.
Extra lifts are also being built to link Paralympians who use wheelchairs with their equipment.
Up to 50 full-time staff are working on a dedicated team preparing Heathrow for the Games. This number is set to spike in the run-up to the Games, including 1,000 volunteers.
Nick Cole, Heathrow's head of Olympic and Paralympic planning, described the London 2012 Games as "a unique operational task and a massive challenge".
He noted: "The airport is one of the most popular international airports in the world and already operates close to capacity.
"Every part of the airport is working together to ensure we can give the athletes a warm welcome and ensure all passengers enjoy the atmosphere."
Security is also an issue which Heathrow, the Host Airport for the Games, is having to grapple with.
A Heathrow document about its London 2012 preparations states: "Our security strategy for the Games is built around existing security processes at Heathrow.
"At present the Games represents no change to the usual risks, although on the busiest days it is likely additional and specialist resources will be deployed to enable a prompt response if needed."
The critical period spanning from 27 June to 1 October has been earmarked as crunch time for the airport in its handling of London 2012 traffic.
This includes time either side of the 27 July Olympic opening ceremony and the September 9 Paralympic Games closing ceremony.
It covers the critical peak times when athletes, officials, sponsors and media, many of whom will have more bags and oversized items than usual passengers, are expected to flood in.
Up to 80% of this Olympic and Paralympic family are expected to use Heathrow, making the airport the first and last impression of the Games for themselves and millions of visitors.
An estimated 59,450 passengers are expected at Heathrow for the Olympics.
This includes 12,850 athletes and 14,700 media who have been accredited by London 2012.
Senior figures such as International Olympic Committee executives, heads of state and other VIPs could account for 2,450 passengers.
Heathrow is now recruiting and training 1,000 volunteers to help cope with demand. They will greet and help arriving passengers.
Heathrow also plans to put its multilingual staff on hand for arriving and departing passengers.
Facilities are also being installed for members of the media to use.
Keeping the flow of road traffic moving outside terminals is another issue and there will be extra coaches for athletes.
A schedule of live tests has been earmarked, where athletes and VIPs will come through Heathrow and try out procedures including volunteer roles, UK Border Agency, dedicated lanes, London 2012 welcome desks and transport.