A quartet of actors you’d never associate with Horse Operas don hats and boots and play at cowboys and gunslingers in “Jane Got a Gun,” a leaden Western with plenty of dead spots between shoot outs.

Natalie Portman has the title role, an 1870s New Mexico mother and wife whose past is about to catch up with her.

Joel Edgerton is the fiance who went off to fight in the Civil War only to return and find her gone, missing from the wagon train she and the daughter he never knew he’d fathered took West. A Missouri gal, she’s always wanted to “go to the Pacific. I wanna step my foot in where there’s no further to go.”

But somehow, when Dan the fiance finds her, she’s already married to Hammond (Noah Emmerich). And how that came to be and the role the cruel wagonmaster and gang leader Bishop (Ewen McGregor) played in it is and what this meandering movie’s many flashbacks are about, and why now, in the film’s fictive present, “Jane Got a Gun.”

Director Gavin O’Connor (“Miracle,” “Warrior”) gives us a dusty, dirty West where the ruthless are forever preying on the weak. Gunfights are brutal, short and finished with a head-shot.

Portman looks good in gloves, Nat-sized hat and dusty overcoat. But the ballerina in her always shines through. She’s a slight thing, but a good enough actress to suggest the inner steel it must have taken any woman to make her way West on her own.

“That girl you rode so far to see — I ain’t her any more.”

Edgerton (“Warrior,” “Black Mass”) looks at home on a horse, in beard and on a bender. Dan crawls into a bottle — for years — until Jane comes for his help. Her husband’s been shot and the men he stole her from, “Bishop’s Boys,” are coming. She needs a gunman.

McGregor, in black mustache and bowler, delivers a decent venality here, but Boyd Holbrook, playing his brother, makes a more sinister and sniveling (and cliched) impression.

The film’s greatest shortcoming — aside from an overdone, melodramatic and eye-rolling finale that is as ludicrous as anything hurled at us in the golden age of B-movie oaters — is pacing. Jane has bad men on the way. Her husband is bullet riddled and dying. And she’s just loping around, marking off her checklist of things to take care of before her reckoning with Bishop — drop the kid off, check, fetch gunman, check, buy dynamite, check.

The action is visceral and exciting, but everything between the shootouts, especially the mostly-insipid flashbacks (A pre-Civil War romantic hot air balloon ride in Missouri? Really?) just makes you impatient for Jane to get that gun and get on with it.

MPAA Rating: R for violence and some language

Cast: Natalie Portman, Ewen McGregor, Joel Adgerton, Noah Emmerich, Boyd Holbrook
Credits: Directed by Gavin O’Connor , script by Brian Duffield, Anthony Tambakis and Joel Edgerton. A Weinstein Co. release.

Running time: 1:38