If a rightwing firearms fanatic stumbles across this absorbing investigative documentary about America’s love affair with the Glock handgun, director Fritz Ofner’s voiceover soon lets them know what they’re in for. Near the beginning of the film he calls the gun’s Austrian manufacturer Glock “merchants of death”. The company is owned by Gaston Glock, 89, a secretive billionaire who might have been ripped from the pages of a John le Carré novel.

Reliable and easy-to-use, the Glock was an instant bestseller when it hit the market in the 80s. It is popular on both sides of the law in the US, as the service weapon packed by many police forces and the go-to gun for gangs. In the brand-conscious world of hip-hop, the Glock has been rapped about by everyone from Wu-Tang Clan to Biggie Smalls (it helps that “Glock” rhymes with a lot of words).

As for the company’s eponymous owner, he doesn’t give interviews. Two business associates have ended up in prison, and both appear here. In a sickening confession, one of them, Glock’s former US lawyer, says that mass shootings are a sensational marketing tool. Ofner visits a jail to interview Glock’s one-time trusted tax adviser, who is serving time for hiring a hitman wielding a rubber mallet to attack his boss in a car park.

Unlike Michael Moore’s Bowling for Columbine, this is not a campaigning film. Ofner doesn’t go after the National Rifle Association or make the case for gun control. Instead, sounding like a softer-spoken Werner Herzog, he interviews an ex-gang member and a gun-shop worker who has a staggering personal collection stored at home in giant safes. There are also desperately sad scenes filmed in Chicago outside the house of a seven-year-old boy shot dead while playing with friends in his front garden.