It was "discovered" among a cache of gold-plated weapons (the explanatory plaque says) by the United States 101st Airborne Division in Kirkuk, and given to an Australian brigadier-general visiting US headquarters in Northern Iraq.

Patrick O'Hara says it's "war booty". He is a former volunteer guide and before that a long-time education officer at the memorial who has resigned in disgust. "Charles Bean designed the memorial to allow people to try to understand what Australian soldiers went through during war. It was designed to show the ugly reality of war. It wasn't meant to be political, gloating or a trophy cabinet," he tells me.

O'Hara loves and respects the War Memorial "and all that it is meant to represent" but he sees the display of the AK47 as "a betrayal of a willingness of the then Australian character to put suffering and courage above politics".

"It's prostitution of the memorial to sensationalism. Iraq is still a mess. The war is still going. Women and children are still being maimed and killed. The invasion of Iraq was illegal."

The gold-plated AK47 is by no means the only kind of souvenir in the museum labelled a "discovery", what may well be seen as plunder. Would Bean, the war correspondent who helped establish the memorial, care? The memorial's website quotes him as saying Australian soldiers were "devoted collectors of battlefield souvenirs and imagined that a museum featuring these objects might be created".

Michael Piggott is an archivist who has written a new chapter on Bean in The Honest History Book, just published by NewSouth Books. He says the memorial's director, Brendan Nelson, loves quoting Bean as an authority to support or counter an argument. He says Bean features almost every time Nelson gives a speech – to give words gravitas, stories authenticity and opinion authority.

True, Piggott tells me, Bean did celebrate scavenging and "souveniring" but the gold gun takes things to another level. "This isn't of the category of grandad's German Luger kept in the attic. It takes it to a bizarre level.

"Bean spent his entire life trying to see how the Australian people were tested in war. The national character, that's what he was on about. If we were to put words into Bean's mouth, they might be: 'How does the display of this golden gun tell us anything insightful about the Australian people?' "

Whatever Bean's (hypothetical) opinion on it, without needing to invoke his name, the gun appears distasteful. It makes the museum less of a sombre place for reflection and more of a Disney-style tourist attraction. What next? A gem-encrusted weapon issued by Syria's Basha al-Assad?

New workers at the memorial are told it's important it retains its five-star tourist rating.

It's easy to forget the impact of guns in such a polished, visitor-friendly space. As Piggott points out: "Gunshot wounds are dreadful things. Bullets, especially hollow-nosed bullets as used in the Boer War, caused gaping exit wounds. You could spend 24 hours in no-man's land, dying slowly, screaming."

From the trenches in Pozières in northern France, Bean wrote in his diary on July 29, 1916, that each shell brought "a promise to each man – instantaneous – 'I will tear you into ghastly wounds – I will rend your flesh and pulp an arm or a leg – fling you half a gaping quivering man (like those that you see smashed around you one by one) to lie there rotting and blackening.' "

The memorial is comfortable with the display of the gold-plated assault rifle. A spokesman says it helps fulfil the role of telling stories about those who serve Australia in war and on operation. Communications head Chris Wagner says: "The gold-plated Tabuk is displayed alongside other examples of insurgent weapons to demonstrate the threats faced by coalition forces in Iraq. In addition, its display also aims to prompt the visitor to the memorial to consider the extreme nature of a regime that would gold-plate its firearms."

At a time when museums are returning Aboriginal remains to the places from which they were taken, it also prompts us to ask questions about ourselves, the stories we not only remember but how we choose to tell them.

Toni Hassan is a writer and an adjunct research scholar with the Australian Centre for Christianity and Culture, Charles Sturt University in Canberra.