A documentary film by an evangelical pastor and a descendant of Walt Disney about America's gun culture has drawn a fierce response from the daughter of former Governor of Alaska and Vice-Presidential nominee Sarah Palin.

Abigail Disney's film The Armor of Light focuses on Pastor Rob Schenck, who was formerly pro-gun but changed his position after meeting Lucy McBath, whose unarmed son was shot and killed.

Schenck is anti-abortion and believes his pro-life position involves campaigning for gun control.

In the film, Sarah Palin is seen addressing a National Rifle Association (NRA) rally and quipping, "Joe Biden, remember this, telling women before an assault just to 'fire a warning shot?'...Gals, you know that nowadays, ammo is expensive. Don't waste a bullet on a warning shot."

In a blog post, Palin's daughter Bristol, a former reality TV star, writes: "The movie is nothing more than liberal propaganda camouflaged as 'thoughtful commentary'." She says that Schenck "spouts leftist talking points" and says that the number of Americans killed by guns is dwarfed by the number killed by abortion. Palin says that she carries a gun and "Christians have a DUTY to carry and protect the innocent." She urges readers to buy her mother's new devotional book to "find out what the Bible really says about topics like this".

The film's producers are using creative ways to boost attendance at its opening on October 30, offering free entry to card-carrying members of the NRA.

Fork Film's distribution executive Jeff Reichert said that Schenck has lost friends over his attempt to get a conversation going. "He is really trying to get Christians to do their moral homework and look at their belief system and ask themselves questions about how their pro-life beliefs fit with this country's gun culture," he said.