In the beginning of “Fury,” tank-crew leader Sgt. Don Collier (Brad Pitt), nicknamed Wardaddy, caves in a wounded Nazi officer’s skull with a swift, unnecessarily brutal crack of his knife. Then he gently pets a white horse before sending it on its way.

The heavy-handed pale horse/death analogy aside, the scene sets the tone for what turns out to be not just another World War II movie. This one depicts “greatest-generation” Americans as the numbed, conscience-free fighters that many had become by April 1945, the final weeks of battle on German soil. They might not have been hanging civilians from lampposts like the Nazis did, but they were killing POWs and armed children, as they were ordered to.

While “Fury” occasionally shocks, it is ultimately not as moving as, say, “Saving Private Ryan.” But writer/director David Ayer has accomplished something arguably more noble, unstintingly sacrificing the sheen of idealism for the less-photogenic truth of war — long periods of slogging through mud and sharing way-too-close quarters interrupted by short bursts of terror and carnage.

“Fury” — the tank’s name crudely painted on its gun barrel — is one of a handful of Shermans, built by Ford, that haven’t yet been blown up by the retreating Germans’ superior tanks, built by Porsche. Wardaddy presides over this dank micro-fiefdom and his four motley charges: an evangelical Christian called Bible (Shia LaBeouf), cynical tough-talker Gordo (Michael Peña, whose excellent, understated performance should earn him leading-man status), crass knuckledragger Coon-Ass (Jon Bern­thal of “The Walking Dead”) and Norman, a bewildered, baby-faced newbie gunner plucked from the typing pool (Logan Lerman of “The Perks of Being a Wallflower”).

The guys reportedly were made to rough it for realism’s sake, spending a week in an English bivouac before shooting, and it shows. LaBeouf looks a good 10 years older than his 28, and even the resolutely handsome Pitt is all eyebags, worry lines and Kim Jong Un haircut.

“Do as you’re told and don’t get too close to anyone,” Wardaddy tells comparatively namby-pamby Norman. Just two months after entering boot camp, Norman was tasked with cleaning the remains of the guy he’s replacing, a hunk of flesh including an ear, from inside the tank. After being ordered to machine-gun a heap of bodies on the ground to make sure they’re all dead, Norman blubbers that he “can’t be here anymore,” to which ol’ tough-love Wardaddy replies, “I promised my men I’d keep them alive. You’re getting in the way of that.”

Later he waxes bluntly philosophical: “Ideals are peaceful. History is violent.” Brow-raisers like these lines might leave you wishing Ayer had chosen his screenplay’s moments of poetic license more carefully.

A scene in which War­daddy invites himself and Norman into the home of a frightened German woman and her comely young niece for a bit of R&R provides visual and psychological relief from the unrelenting, run-together olive drabs, grays and browns of the barren battlefields, at times indistinguishable from the soldiers’ uniforms. But it goes on too long for an off-key, hard-to buy segue, a fleeting romance between Norman and the girl.

In a suspensefully staged if predictable climax, the underdog quintet face off against an SS brigade, staggeringly outnumbered. “Fury” may not be the most memorable of World War II movies, but it’s a visceral ride.