The Colt 1851 Navy revolver is the sidearm carried by most of the Union officers in the film, notably Colonel Robert Gould Shaw (Matthew Broderick) and Major Cabot Forbes (Cary Elwes), who use them during the 54th's first engagement.
Enfield Pattern 1853
The reproduction Enfield Pattern 1853 rifle, made by EuroArms, London Armoury, used by the men of the 54th in the film. Also seen used by Confederate Troops as well. Incorrectly, the rifle muskets are presented as having serial numbers, which original Enfields lacked. As well, the EuroArms reproduction Enfield is actually of a variant which was NOT brought into North America during the Civil War. Instead, it represents the variant which was used in the Snider conversion.
Howitzer
The confederate troops appear to use large Howitzer cannons during the civil war battle