Springfield Rifle: The primary infantry rifle was the M1903 Springfield, officially known as the United States Rifle, Model of 1903. It was a bolt-action rifle that fired a .30-06 Springfield cartridge. It was generally accurate, reliable, and popular with American soldiers, although in many aspects, it was inferior to the German Mauser rifle, particularly because it had a slower rate of fire and lacked features such as a high-capacity magazine or stripper clip.
Colt 1911 Pistol: The M1911 was a semi-automatic pistol that fired the .45 ACP cartridge. It was designed by John Browning and adopted by the United States Army in 1911. It was a popular and effective weapon, and would remain the standard United States military sidearm until the 1980s.
M1918 Browning Automatic Rifle (BAR): The Browning Automatic Rifle was a squad-level automatic weapon introduced in 1918. It fired .30-06 cartridges, and while heavy, provided increased firepower at the company and battalion level.
As the Americans entered the war in 1917, they were largely out-equipped and their supply of military equipment was limited, so they primarily used French and British equipment such as the Hotchkiss machine gun, Chauchat automatic rifle, and Lebel rifle, until their own industries could catch up to meet the demands of war.