Shooter is juicy and meaty, but no savory sirloin. Inhale it like a Thickburger, before the dripping grease congeals on your fingers and you think too much about what you’re wolfing down.

Strong violence and language earn it an R rating. So could the graphically charming way it makes you clap those sticky hands at the vaporized heads, amputated arms and blown-away faces. But feeling dirty about reveling in its rowdy outlaw righteousness is part of the movie’s wily fun.

Mark Wahlberg trades native Boston for the backwoods in this adaptation of Point of Impact, a novel by Washington Post film critic Stephen Hunter. Hunter loves munitions stats, graphic murder, and splashing testosterone like dime-store cologne. (Wahlberg’s slo-mo struts add exclamation points to his military sniper, who bears the hillbilly-deluxe name of Bob Lee Swagger.)

Shooter updates Point’s politics from an era when William Shatner hosted any TV segment that included the numbers 9-1-1. It’s also not as grub-deep Southern as the book, moving Swagger to Wyoming from Arkansas. But this thrilling, if overlong, B-movie loses none of the stinging sweat, shock or slyness of Hunter’s prose.

On duty in Ethiopia, Swagger and his partner, Donnie, track wind, angles and distances for accurate obliteration of bad-guy brains. Quickly outgunned and under attack, Swagger and Donnie trade fire with a helicopter, but only Swagger lives. Director Antoine Fuqua (Training Day) is so attuned to Hunter’s eye for detail that the story then shifts not three years, but “36 months,” later.

Swagger now is a recluse in Wyoming’s mountains, but gets good wi-fi and cell service in them thar hills and has a dog with TV-commercial ability to fetch Bud from the fridge. Enter Colonel Isaac Johnson (Danny Glover). He solicits Swagger to prevent a presidential assassination by way of hypothesizing possible plans. So Swagger cuts his Metallica-bassist ponytail and reports for duty during a stump in Philadelphia.

When rifle reports really ring out, Swagger spots a setup, but suffers gunshot wounds and a multiple-story fall. On the limp, he accosts new FBI agent Nick Memphis (Michael Peña), but quickly proclaims innocence before taking Memphis’ car. After an exciting escape from Philly, Swagger lies low to recuperate and then retaliate against political puppet-masters who crossed him.

Usually uncorked in character parts, Wahlberg too often leans toward passably bland leading-man roles. Here, he morphs Swagger more into a muted line of military stoicism. Swagger is no one-man wrecking machine, and he knows the value of a spotter, if not two, in helping him out.

One is Donnie’s widow, Sarah (Kate Mara, fetching and feisty), whose trust Swagger earns not by happenstance but by months of respect through writing letters and sending flowers. Another, eventually, is Memphis, who doesn’t buy the lone-gunman suspicion against Swagger. After Crash and World Trade Center, Peña definitely is an actor to watch. His Fed chooses mouth and mind over muscle, and his blend of dogged determinism and a ninny’s fear provides great levity.

Pena’s pipe-offs are just a round in a full clip of Shooter’slaugh-out-loud moments, such as Swagger’s description of Tennessee, actor / musician Levon Helm’s turn as a Foghorn Leghorn-esque gun nut and, best yet, that bad guys hack into the FTD database to gain leverage on Swagger.

Shooter has one triple-super sudden-death revenge overtime too many, the right outcome by the wrong method and a tendency to sometimes feel like a backwoods Bourne Identity. But its politics are pointed and potent, and Fuqua delivers sturdy action scenes. The best is Swagger’s siege of a farm, with arguably the best cinema combo of helicopters and napalm since Apocalypse Now. That’s just all part of the smell of victory for this cinematic piece of trashy fast food.