I first saw this film at Valley Forge National Historical Park. The National Park Service had a 16mm print and used the film to train rangers in 18th Century warfare. That's how historically accurate it is. Ball versus grapeshot. Musket shot versus bayonet. Movement and flanking. And lastly, the arrogance and stupidity of leadership on both sides. Always a lesson to me.
You no longer have to work at Valley Forge to see it. It's on DVD and well worth adding to your collection if for no other reason to remind us all that incompetence and war usually go hand in hand.