Love that movie - lots of great character actors, plus Bill Mauldin - and using actual 1863 muskets. The only jolt I got was at the river crossing where the troops were holding their muskets above their heads, and outlined for a split second, was a 1903 Springfield. No wonder the North won.
***and outlined for a split second, was a 1903 Springfield. ***
If you watch the Russian version of WAR AND PEACE (1967) the battle of Borodino you will see some Russian troops in the background using bolt action Mosin-Nagant rifles.