The Galleries
- Robert E. Petersen Collection
- Ancient Firearms - 1350 to 1700
- Road to American Liberty - 1700 to 1780
- A Prospering New Republic - 1780 to 1860
- A Nation Asunder - 1861 to 1865
- The American West - 1850 to 1900
- Innovation, Oddities and Competition
- Theodore Roosevelt and Elegant Arms - 1880s to 1920s
- World War I and Firearms Innovation
- WWII, Korea, Vietnam and Beyond - 1940 to Present
- For the Fun of It
- Modern Firearms - 1950 to Present
- Hollywood Guns
Richardson & Overman Gallagher Carbine
Although inventor Mahlon J. Gallagher was a native South Carolinian, over 23,000 Gallagher carbines manufactured in Philadelphia during the Civil War for issue to Federal cavalry units.