A Majority of the residents of 1865-era New York all carry small single-firing boot pistols as their means of protection
Colt Model 1849 Pocket Model
During the Theatre Scene an Assassin (Bronco Mcloughlin) attempts to kill Bill "The Butcher" Cutting (Daniel Day-Lewis) with a Colt 1849 Pocket Model Revolver
Double Barrel Shotgun
During the Draft Riot, William Tweed (Jim Broadbent) walks to his office window, cocking the hammers of a double barrel shotgun
Elgin Cutlass Pistol
Amsterdam (Leonardo DiCaprio) attempts to assassinate Bill "The Butcher" Cutting (Daniel Day-Lewis) by throwing a knife and then pulling an Elgin Cutlass Pistol, only to be impaled by a knife thrown by Cutting
Colt 1851 Navy Revolver
During the Draft Riots Scene, a mob breaks into Mr. Schermerhorns (David Hemmings), and he in turn uses two Colt 1851 Navy Revolvers akimbo style
Sharps Rifle
During the scene where William Tweed (Jim Broadbent) is conversing with Dead Rabbit supporters, Jenny Everdeane (Cameron Diaz) keeps a Sharps Rifle aimed on him
Rogers & Spencer
During the scene where William Tweed (Jim Broadbent) is conversing with Dead Rabbit supporters, Amsterdam (Leonardo DiCaprio) appears to have a Rogers & Specer revolver tucked into his waistband.
Springfield Model 1842 Musket
An Irish imigrant is seen being issued a Springfield Model 1842 Musket. This is historically correct, as the Irish Brigade were issued the 1842 Musket until 1864, as it was preferred for it's ability to use the "buck and ball" load.
Some US Army troops are seen carrying British Enfield 1853 rifles, which were commonly issued to Union regiments. They would not, however, have been used side-by-side with Springfields in the same unit.
Unknown Firearms
There are numerous firearms in the movie that are hard to identify