@farmerman,
Nope. As Chamberlain aged after the battle, he went from saving his brigade, to saving the army to, eventually (when he was running for governor of Maine) saving the nation. There were five regiments in Col. Strong Vincent's brigade. It was a good thing that the 20th Maine held. But if any of the other four regiments had broken, the brigade would have been swamped. It would not have spelled disaster for Meade's army, although it would certainly have been awkward. On that basis alone, Chamberlain's claim can be dismissed.
However, men in the 20th Maine, not initially aware of the claims Chamberlain was making, began to dispute his version of events as his narrative became public. I recommend
The Gettysburg Nobody Knows by Gabor Boritt, Director of the Civil War Institute at Gettysburg College (Oxford University Press, 1997). One of the articles in his book carefully reviews Chamberlain's claims, and the contradicting testimony of private soldiers and officers who were veterans of the 20th Maine.
Both Shaara's novel and the motion picture are poor in detail, and so give a distorted view of the course of the battle. John Buford, commanding the First Cavalry Division, had moved into an encampment west of the town. He sent out vedettes to keep an eye on Lee's army, which was known to be to the west, and marching north. His troopers skirmished with Heth's infantry on the morning of June 30. Late on June 30, his patrols found Lee's army, but the portion they made contact with, Harry Heth's division, wasn't moving. Early on the morning of July 1, his patrols raced in to tell him that the Confederates were marching east. As it happened, that was Heth's division, about 7000 strong (Lee's divisions were massive compared to those of the Federal army) and Pender's division, only slightly smaller. Buford began the day with no back-up, and he only had two the three brigades of his division. His troopers put a stiff resistance, certainly, but from the novel and the movie, one would think that's all that happened on the first day. Cavalry were expensive, expensive to train, expensive to equip and expensive to replace. As soon as Reynold's First Corps came up, Buford retired. Riding northeast from McPherson's Ridge, the encountered and captured a major portion of Archer's brigade from Pender's division. That was the end of Buford's Gettysburg, and he had done very well.
But then the novel and the movie move on to the second day, as though nothing else happened on the first day. First Brigade, First Division, First Corps, command by Col. Merritt, stopped both Heth and Pender long enough for the rest of that corps as well as XIth Corps to come up. They suffered 80% casualties in that fight, but retired in good order, taking their dead and wounded with them. They had fought Heth and Pender to a standstill. You'd never know it from the book or the movie.
I'm just barely started, but i think you get the point. I suspect you know enough about the battle to know just how much hogwash there is in that movie.
(A good account of Buford can be found in
The Cavalry at Gettysburg, Edward Longacre--sorry i don't have a publisher or date--some time in the 1980s.)
