Browning designed the .38 ACP (Automatic Colt Pistol) cartridge for use in the Colt Model 1900 pistol. It was a pioneering cartridge for semi-automatic handguns.

Browning designed the 9mm Browning Long cartridge for the FN Model 1903 pistol. While not a high-powered cartridge, it was adequate for military and police use in its time and is still used today as the .380 ACP.

Browning designed the .25 ACP (Automatic Colt Pistol) cartridge for the FN Model 1906 pistol. This small cartridge made the handgun easier to conceal.

Browning designed the .45 ACP (Automatic Colt Pistol) cartridge for use in the Colt M1911 pistol. Its adoption by the US military solidified it as a powerful and effective handgun round.

Browning designed the .50 BMG (Browning Machine Gun) cartridge for his .50 caliber machine gun. This powerful cartridge remains in use for a wide range of applications, from anti-material rifles to vehicle-mounted weaponry.