Former congresswoman Gabrielle Giffords delivers a speech in an archival scene from the documentary “Gabby Giffords Won’t Back Down.” Briarcliff Entertainment photo

On the heels of their documentary portraits of activism with a human face, “RBG” and “My Name Is Pauli Murray,” filmmakers Julie Cohen and Betsy West have turned their camera on another remarkable subject: Gabrielle Giffords, the former Arizona congresswoman who, after being wounded in a 2011 assassination attempt at a public event in her home district, recovered from a gunshot to the head at point-blank range to become an outspoken advocate for gun control. That’s the elevator pitch for “Gabby Giffords Won’t Back Down,” but it doesn’t quite convey the moving arc of courage and perseverance laid out in the film, which opens with amateur video footage of its subject, sitting in a hospital bed not long after the shooting, as she begins the long road to recovery.

Giffords’s head is shaved, with sutures still visible from a large, ugly incision. She smiles but cannot speak. The film and the ticktock of recovery it follows are at times difficult to watch. At the same time, watching feels almost necessary in an age when mass shootings seem to have become all too common.

“Won’t Back Down” contains a little bit about the shooter, Jared Lee Loughner, and the day of the shooting and its aftermath, which left several people dead. But it doesn’t dwell overly long on Loughner’s disturbed mental state or incoherent motive, his subsequent trial and sentencing, or his access to guns – although all these things are touched upon. Instead, Cohen and West wisely focus mainly on Giffords herself and her painstaking rehabilitation. (Today, she suffers from aphasia, speaking passionately yet haltingly, as well as vision loss. She walks with a limp – all the result of the bullet that tore through her brain.)

But the bright light of her personality has not dimmed. This is attested to in interviews with such talking heads as former president Barack Obama, who calls Giffords a “star” – one who seemed poised to rise as high as she wanted to in politics, at least before the shooting. That bright light is also demonstrably present in recent interviews with Giffords, several of which take place by the side of her husband, Mark Kelly, a former astronaut and now senator from Arizona who has, in some ways, picked up the torch his wife set aside. Giffords is now the public face of Giffords, a gun-control advocacy organization that works to elect politicians who will fight for common-sense gun laws. In a clip of Kelly from a campaign debate with his Republican opponent, Martha McSally, McSally calls the group a “radical political organization.”

But the person who expresses herself most powerfully in “Won’t Back Down” – which takes its name from the 1989 anthem of stick-to-itiveness by rocker Tom Petty, playing in the background of one scene – is Giffords herself. Near the film’s inspiring conclusion, we hear Giffords say, with great grit and only after difficult practice, “Words once came easily. Now I struggle to speak, but I have not lost my voice.”