Revenge is served cold. Sometimes it’s served piping hot. And it’s served again and again, until the gunmen retreat into the foggy woods.

Over six hours that span 25 years, “Hatfields & McCoys” chronicles America’s most famous family feud, a bloody conflict that ravaged two Appalachian clans in the decades after the Civil War.

The History channel production has an impressive pedigree: As the fathers of the warring families, Kevin Costner and Bill Paxton lead a cast that includes Tom Berenger, Mare Winningham and Powers Boothe.

As the opening credits roll, Anderson “Devil Anse” Hatfield (Costner) and Randall McCoy (Paxton) are in the thick of battle, but they’re still on the same side, fighting Yankees. The Civil War skirmishes serve up the first taste of the carnage that pervades the next six hours.

“Hatfields & McCoys” isn’t shy about making the case that Devil Anse and Randall came back from battle desensitized, angry and untethered. It’s no coincidence that this story of damaged veterans begins on Memorial Day.

Devil Anse does a lot of talking about peace after he gets home, but his trigger-happy brother-in-law Jim Vance (Berenger) has other ideas, especially about a McCoy who fought for the Union. A rifle shot rings out in the thick Kentucky woods. Harmon McCoy’s children find their father’s body in the snow. And so it begins.

“Hatfields & McCoys” keeps the preaching to a minimum, even if a minister does get a bloody lip from a bounty hunter at one point. If we learn nothing else from this brutal examination of a feud marked by more than a dozen murders, it’s that you don’t want to go up against a man whose own children call him Devil.

Filmed in the wilderness of Romania, the miniseries has a convincing look, thanks to dead-on costuming and set design. “Hatfields & McCoys” neatly compresses events and distills the wrangling over elections, timber rights and illicit romances that added fuel to the fire, not to mention the infamous trial over hog ownership that really got things rolling in 1878.

The murder that follows the hog verdict is a good time for the squeamish to get some popcorn, and at this point the level of front-and-center violence makes it clear that “Hatfields & McCoys” has waited too long before giving the audience anyone or anything to root for.

With no side worth taking and a camera that refuses to pull away as three brothers are tied to trees and riddled with bullets, “Hatfields & McCoys” transforms into a numbing shooting gallery whenever the plot speeds up.

In quieter moments, it’s a lesson in family dynamics. These are clans heavy on instigators — slimy McCoy cousin Perry Cline (Ronan Vibert) uses his law degree to keep the warrants and bounty hunters flowing across the Tug River, while Vance ups the ante by attacking wives and mothers. The matriarchs are understandably in a constant, low-key panic, but the younger women, especially the McCoys, aren’t exactly ringing the bells for peace.

Nancy McCoy (Jena Malone) makes the most of her station in life to exact revenge. The daughter of Harmon McCoy betrays, marries, betrays again and marries again, all in a cold-hearted campaign of hatred. Her wails of rage and sorrow upon hearing of her brother’s death at Hatfield hands punch through the tight-jawed silence that passes for grief elsewhere in the series.

Eventually, without lifting a rifle, Nancy kills as coldly as any man on either side of the river. Malone (“Pride & Prejudice”) makes her one of the few murderers on the screen you wouldn’t mind knowing more about.

When one of the patriarchs finally declares, “Somebody’s gotta bend to stop it,” relief follows only after a public hanging of the least deserving gunman possible.

“Hatfields & McCoys” earns credit for not slapping a redemptive ending on such a grim journey. The Hatfields, who were more affluent and connected to begin with, come out a little better by the time things cool down in 1888. But there’s no moral high ground in this corner of the mountains.