The M5 used fixed ammunition, with the same 76.2x585R cartridge case – designated 3 inch Cartridge Case Mk IIM2 – as other descendants of the 3 inch M1918 anti-aircraft gun, and had basically the same barrel.
The M5 employed standardized ammunition, utilizing the same 76.2x585R cartridge case – known as the 3 inch Cartridge Case Mk IIM2 – as other offspring of the 3 inch M1918 anti-aircraft gun, and shared a similar barrel.