Manufacturers of the .45 ACP 1911 Pistol could not keep up with the demand of the U.S. Military during WW I. Two pistols were chosen as a stop-gap measure. One pistol was produced by Colt and was called the New Service Model pistol. The New Service Model had already proven itself for some time with the British Army chambered in the British .455 Webley cartridge. The Colt pistol (United States Revolver, Caliber .45, M1917) was chambered in the .45 ACP cartridge and was loaded by either three round stamped metal half moon clips or six round full moon clips. This type of loading system allowed the soldier to quickly load and unload the pistol three or six cartridges at a time. The revolvers had a blued finish when first manufactured but some were rearsenaled later near and during WWII and had a parkerized finish applied as the model pictured above does.