Abigail Disney’s documentary “The Armor of Light” follows the Rev. Rob Schenck, a Christian activist who supports gun control. (Jeff Hutchens/Fork Films)

As a portrait of Rev. Rob Schenck — a politically conservative evangelical Christian minister who has defied his natural constituency to become a soft-spoken supporter of gun control — “The Armor of Light” is a fascinating little piece of storytelling. In this documentary by Abigail Disney (Walt’s grandniece), we learn that Schenck, a longtime anti-abortion activist and founder of the Washington religious outreach group Faith and Action, had a epiphany after the 2013 Navy Yard shootings: It was no longer possible — for him, at any rate — to reconcile his beliefs with pro-gun politics.

Few of those to whom his organization ministers most fervently — congressional Republicans of the Tea Party persuasion, as he describes it — see things his way.

To call Schenck’s stance on guns quixotic is putting it mildly. Although the film charts Schenck’s partnership with gun-control activist Lucy McBath, whose son, Jordan Davis, was shot and killed in 2012 by a motorist annoyed by the teen’s loud music, much of “Armor” documents Schenck’s encounters with less like-minded folks. One conversation in particular, set over lunch with a handful of anti-abortion activists, is frustratingly futile. Operation Rescue president Troy Newman, for instance, angrily spouts off about the “nanny state,” repeating the statistically unsupported gun-lobby mantra that “the only thing that stops a bad guy with a gun is a good guy with a gun.”

If this is what passes for constructive dialogue among friends, may the good Lord help Schenck. He’ll need it.

At other points, Disney includes equally distressing archival clips: Sarah Palin urges attendees at the 2014 NRA Convention not to “waste a bullet” on a warning shot at an intruder. And Rev. Franklin Graham (son of evangelist Billy) draws a specious equivalency between sensible efforts to regulate guns and a government conspiracy to take them away from law-abiding citizens.

From a personal perspective, Schenck’s story is a compelling one. Raised in a culturally Jewish household, he converted to Christianity, devoting his life to the anti-abortion movement. Many years later, when he came to believe that his conviction about the sanctity of fetal life was incompatible with support for “stand your ground” laws and other manifestations of what the film portrays as the “gun culture,” Schenck began speaking out — albeit quietly and prayerfully — on the subject.

That’s a great, counter-intuitive story.

The film also spins a larger political narrative, although Schenck’s efforts to convert other God-fearing conservatives to his cause are met with universal resistance. “The Armor of Light” feels less like a rhetorical draw than watching a man bang his head against a wall.

The reverend may be girded with the “armor or light,” as he puts it, quoting the Bible. But his opponents — or at least the ones shown in the film — have seemingly strapped metaphorical Kevlar around what appear to be permanently closed minds.

Unrated. At Landmark’s West End Cinema and Regal Majestic. Contains mature thematic material and some disturbing images. 87 minutes.

On Friday, the West End Cinema will host a Q&A with Rev. Schenck following the 7 p.m. show; he will also introduce the 9:30 p.m. show.