It's hard to argue with a man who, as the memorial's head of military heraldry and technology, has enough planes, tanks, rockets, helicopters, trucks, half-tracks, armoured personnel carriers, cannons, howitzers, machine guns and guided missiles to fight a medium-sized war back behind his barbecue pit.

He said that on a good day, when he's out amongst the collection rather than looking at a computer screen or pieces of paper, it's the best job in Canberra.

Mr Fletcher and the AWM's staff are gearing up to show off some of the memorial's rarely seen treasures at the annual "Big Things In Store" day to be held at the Treloar Technology Centre in Mitchell on Saturday, September 10, from 9am to 3pm.

With entry by donation it is arguably the most bang anybody will ever get in the ACT for their buck and an outing every family can afford.

One vehicle worth seeing this weekend is the M577 armoured control vehicle used by Major "Blue" Keldie during the Battle of Coral-Balmoral from May 12 to June 6, 1968.

Mr Fletcher said the vehicle was one of the legendary 113 series of armoured personnel carriers that were used by Australian forces for more than half a century.

"They've been in service for a very long time," he said. "The M577 command variant, of which we only ever had a very small number, have seen a lot of service in various theatres. This particular example, 134456, has the distinction of being the longest serving tracked vehicle in the ADF I believe.

"It served longer in Vietnam than any other vehicle and we've not had tracked vehicles go overseas [for combat operations] since. It was also the command vehicle for the defence of Fire Support Base Coral.

"It's final operational deployment was to East Timor with 5 Battalion, Royal Australian Regiment. Following that it came back to Australia and we finally retired it."

Another machine that has played a significant part in Australia's battlefield history is the Bell H3 Sioux helicopter flown by Captain James Douglas Campbell on the mission on February 21, 1967, that resulted in him being awarded the Distinguished Flying Cross.

An armoured personnel carrier had hit a booby trap and when men from another APC went to the aid of the crew they set off a claymore mine.

By the time Captain Campbell arrived at the scene with a medical officer seven Australians were dead and 26 had been wounded.

The veteran Army pilot set down in the minefield to rescue the wounded, taking off and landing repeatedly to ferry the most seriously injured to safety aboard his three-man machine.

"You can tell they [the Bells] are a first generation helicopter," Mr Fletcher said. "They don't have a lot of mod cons; they are quite a primitive looking device.

"It was a pretty catastrophic scene [in 1967]. It was a very well earned DFC."