So, David Barton, in an article on his WallBuilders website, has finally responded to the question of where he got the story he told on Glenn Beck's web-based TV show about a classroom full of gun-toting elementary school students saving their teacher from a gunman in the 1850s. As suspected, the story did come from Louis L'Amour's novel Bendigo Shafter. But Barton, who incessantly claims to use only primary sources, and constantly accuses anyone who criticizes him of not using primary sources (even when they do), defends his use of the story because L'Amour, in a recorded introduction to the audio version of one of his other stories, said it really happened:
There's a case I use in one of my stories; I use it in the story called Bendigo Shafter. All the kids coming to school used to hang their guns up in the cloakroom because they were miles from home sometimes, and it was dangerous to ride out without a gun. And this is taken from an actually true incident. I use it in my story and tell the story, but it really happened. Now a man came to kill the teacher. It was a man. And he came with a gun, and all the kids liked the teacher, so they came out and ranged around him with their guns. That stopped it. But kids twelve and thirteen used to carry guns to school regularly.
Now, L'Amour did do research for his novels, and probably had some sort of source for the incident that he based his story on, but we still don't know what that source was. L'Amour, in the same audio introduction said he used diaries, books, and newspapers. One book that he singled out as an example of a good source was a book written by a woman who had grown up in Deadwood, South Dakota, but if you look at that book (as I did, of course), you see that much of it was the woman's recollections many decades later of things that happened when she was a very young child, making its details about as reliable as those in Laura Ingalls Wilder's Little House books. Reliable enough for a fiction writer? Yes. Reliable enough for an historian? Not so much.
Without the where and when details of the incident that L'Amour based his gun-toting students story on, and not even knowing whether he got the story from a newspaper, someone's book or diary, or just from someone telling it to him, it can't be verified. We don't know if it was exaggerated by whoever L'Amour heard it from, or if he further exaggerated it to make his novel more exciting.
Look at how much the details of the story changed just from the version in L'Amour's novel to the version told by Barton:
Barton said the incident happened in the 1850's, although Bendigo Shafter was set later than the 1850s. (A number of references in the novel clearly place the time of story no earlier than the 1860s, including a reference made very near the beginning of the novel to Bendigo being given a book that L'Amour makes a point of saying was published in 1859. In the story, this was before the man who would later become the school teacher had even arrived in the town, so the earliest that the gun-toting students story would have occurred was the 1860s.)
Barton, in his version of the story, also said that the gunman who came to the school had followed the teacher from New England. But in Bendigo Shafter the gunman was after the teacher for gunning down two of his friends after a poker game in San Francisco.
See how much a story can change in just one retelling? A gunman from San Francisco in the 1860s became a gunman from New England in the 1850s. How much might the story have already changed from whatever incident L'Amour based his novel's version on? This isn't a reliable historical source; it's a game of wild west telephone.
To quote you yourself, Mr. Barton: "A similar corollary would be to study the life of Jesus only by reading The DaVinci Code."