War is hell, and so, to a lesser degree, are war movies.
On the set of Fury, which follows an American tank crew through the wreckage of northern Germany in the final days of the Second World War, the actors - among them Brad Pitt and Shia LaBeouf - heckled, strangled and swung punches at each other during filming.
Villagers near the Oxfordshire set were woken in the early hours of Remembrance Sunday last year by the sound of explosions and the sight of SS men swarming the countryside (the director, David Ayer, later apologised for the timing).
There were black eyes, bloody noses and bloody mouths, and one unfortunate stuntman, mistaken for a dummy, was bayoneted through the shoulder (he survived).
The five actors who make up the crew of Fury, a Sherman tank - Brad Pitt as Wardaddy, the commander; Shia LaBeouf as the Bible-bashing gunner; Michael Pena, as the driver; Jon Bernthal as the loader; and Logan Lerman as the youngest and greenest member of the team - had already spent weeks together before their first day on set, at a specially-tailored boot camp run by ex-Navy Seals.
"We're just tourists in the war experience," says Pitt, who looks scarred and menacing on screen, but as crisp as a €50 note off it, sitting in a vast hangar at Bovington Tank Museum in Dorset.
"But we were put to a point of exhaustion and no rations and no showers and we were sleeping in the rain, and it was miserable and we loved it."
As the commander of Fury, Pitt was given slightly better treatment than his men - a separate bunk, for example - and his memories don't necessarily tally with theirs. "To be honest, I look at the whole process as being pretty dark," says Bernthal. "I took a year off afterwards," says 22-year-old Lerman, "because this was a very difficult experience".
All the same, a sort of pack mentality had set in by the time filming began. "I'll never forget that first day," says Bernthal, a classically-trained actor and former boxer.
"In the screen test, I know it sounds crazy, but people were, like, exposing themselves and fighting. I remember some of the crew saying they were actually scared of us."
This was all the intention of Ayer, the film's director. Ayer is a military veteran himself, having joined the US Navy when he was 18 and served for two years in a nuclear submarine.
That experience inspired him to write his first screenplay, U-571, a film that was attacked in Britain for suggesting that the German Enigma coding machine was captured by an American submarine crew.
In fact, it caused a minor diplomatic incident, with then prime minister Tony Blair calling it an "affront" to British sailors, and Bill Clinton writing a letter of apology for the movie's inaccuracy.
This time, Ayer was determined to make his story as truthful as possible.
"In Second World War dramas there can sometimes be a tendency to mythologise the experience of the soldier and mythologise the nature of the combat. Obviously the enemy was so horrible that we think that the fight itself was black and white, but it wasn't, just like any war. War is always complex, war is always morally difficult, war forces individuals to make terrible choices."
Ayer took a hands-on approach to every detail of the film, from the battered appearance of the uniforms -to the weaponry.
"He's seriously a military junkie," says Pitt. "The depth of detail in the film was staggering."
Ayer studied army signal corps photographs with a magnifying glass.
"I think in my business, oftentimes people study other movies, and when you do that you can end up repeating the institutionalised traditions of a genre."
The tanks were the most important piece of the puzzle. the Americans' Sherman M4, known as the "Tommy-cooker" for its propensity to burst into flames on being hit, and the German Tiger, a tank which acquired an almost mythical status during the final years of the war. One British soldier wrote at the time that the Tiger, clad at the front with thick armour, and armed with an 88mm gun originally devised as an anti-aircraft weapon, provoked "hysterical fear" in his compatriots.
For the scenes of battling tanks, which are some of the movie's most visceral, a replica Tiger was built, cut from steel a quarter-inch thick and placed on a smaller tank base, with the wheels and tracks added in post-production.
The Sherman M4E8, a late-war model with a high velocity 76mm gun, was another Bovington find.
The night before shooting the actors slept on top of the tank. "I think we all fell in love with the Fury," says Ayer. "Normally when you call cut, the cast disappears. In this case they would just go inside the tank and hang out and spend time among themselves. I know it would be hard to get Brad out of it."
Pitt agrees: "It wasn't made for man or beast, truly," he says. "There's nothing ergonomical about it, and yet you find your little space of comfort. Very quickly it became home."
"I have shots of Brad just walking right up it like it's a set of stairs," says Ayer. "Like a gazelle," adds Pitt.
Fury is on general release in Ireland. on Wednesday.