American Sniper is not just a triumph for Clint Eastwood but for Bradley Cooper as well. Despite two Oscar nominations, Cooper has never fully been able to shake his pretty boy reputation nurtured by the Hangover movies. However, for the first time, Cooper literally disappears within a role. He added forty pounds of bulk, almost all of it muscle, to play the title role of Chris Kyle, and his Texas twang seems perfectly natural.

Kyle was the most decorated sniper in U.S. military history. A Navy SEAL, he was credited with well over 100 kills and probably killed well over 200 enemy combatants. During his four tours of duty in Iraq, he became widely known to friend and foe. Other soldiers gave him the nickname “Legend” while Iraqi insurgents placed a six-figure bounty on his head.

American Sniper is a somewhat fictionalized story of Kyle’s life, based on his best selling memoir of the same name. In fairly standard but efficient fashion, the movie follows Kyle through basic training and a romance and eventual marriage to Taya (Sienna Miller). Because of the sharpshooting expertise he had developed since childhood, he became a sniper and assumed the mentally and physically demanding job upon arrival in Iraq.

After the initial conquest of Iraq, much of the fighting took place in Baghdad and other cities and towns, where slow moving U.S. troops and vehicles were often inviting targets for an enemy that hid in buildings and alleyways, waiting for an opportunity to throw a grenade or unleash a car bomb attack. Kyle provided cover to the troops, picking off enemy threats before they could get close enough to attack. His task was extremely difficult, not just because of the difficulty of hitting his targets at a great distance, but also because none of the combatants were uniformed soldiers. Instead, they were civilians, including a number of women and children, and Kyle had to be sure of his targets’ sinister intentions since a mistake could end his career.

Not surprisingly, the stress of the job takes its toll on Kyle. He asks for a more direct combat role, often accompanying other troops going house to house. Still, despite his efforts, American troops continue dying, and the local populace remains hostile. He becomes more distant, especially from his family. Even after he returns home after his last tour, he is still plagued by his mental problems.

American Sniper struggles at times to figure out how best to portray Kyle’s mental problems. While Bradley Cooper’s performance is spot on and subtle, showing a man who isn’t quite right, the movie itself is never quite right either. The screenplay by Jason Hall creates a story line about Kyle’s ongoing “duel” with a Syrian sniper Mustafa, who’s portrayed as Kyle’s sinister doppelganger. While Mustafa was real, Kyle was never involved in any combat involving the man. However, in the film, Kyle’s quest to kill Mustafa, who killed some of Kyle’s friends, gives the action scenes focus and explains both why Kyle kept coming back to Iraq and, eventually, why he left.

Later, Kyle explains to a psychiatrist why he is troubled. In his view, he’s not upset about anything he did in Iraq, but, rather, about the soldiers that he wasn’t able to save. That statement certainly reflects Kyle’s attitude as expressed in his memoir. However, whether that’s the only reason that Kyle had mental issues is open to question, and the film suggests that the reasons for his stress were far more complex. The screenplay is remarkable subtle in its depiction of Kyle’s mental state.

One thing that’s not complex or subtle in American Sniper, however, is how Kyle got his life back together. According to the movie, he started working with wounded and injured vets and, by helping them overcome their problems, he wound up curing himself. That may be true, but in the movie, it takes Kyle two brief scenes and about three minutes of screentime to get his life back together. Such a casual depiction of Kyle’s mental rehabilitation trivializes his condition in the first place, especially since viewers have seen nearly two hours of his suffering until then. It’s the equivalent of showing an alcoholic becoming rehabilitated after attending a single A.A. meeting.

In most regards, however, American Sniper is a stunning movie. The action scenes are brilliantly staged and photographed. Throughout the complex, confusing battle sequences, viewers are easily able to follow the action and understand just who’s shooting and where they are (the one understandable exception is a sequence in which a sandstorm eventually obscures visibility). The editing is also excellent, building a tremendous amount of suspense in key sequences in which the action literally stops as characters try to make decisions. American Sniper is easily Eastwood’s most accomplished film since Letters from Iwo Jima.

The definitive film about the war in Iraq remains to be made, and, indeed, it may never be made. However, until that happens, American Sniper can serve as a more-than-capable stand-in. The movie captures the chaos and psychological pressures of the war, as well as the valor and continued optimism of our forces. At the same time, it shows, perhaps not in quite as much detail as it should, the physical and mental toll the war took on American forces. The war in Iraq may have been particularly hellish, but American Sniper provides the best cinematic insight yet into the conflict.