The new design also featured a new cartridge, the .38 Automatic Colt Pistol. Despite the name, this cartridge used a .357 caliber bullet weighing , at a muzzle velocity of , a tradition born when the earlier .38 Special switched from heeled bullets to smaller-diameter inside-lubricated bullets, yet retained its original ".38" designation (and only broken upon the introduction of the .357 Magnum in the 1930s). This was a larger caliber bullet than used by other contemporary designs, which were predominantly 7.6 mm, or .308 caliber (i.e., 7.62×25mm Tokarev/7.63×25mm Mauser, .32 ACP, etc.), yet fired at similar velocities, giving more power. The .38 ACP was also a much faster cartridge than the .38 Long Colt revolver cartridge in service at the time, which fired a bullet at (albeit 130 grains being a heavier bullet). Colt was also experimenting with a .41 caliber cartridge for use in the Model 1900, as reported to the Ordnance Department during testing. Like the .41 Long Colt, this probably used a .400 inch bullet. The poor performance of the .38 Long Colt in combat in the Philippine–American War of 1899–1902 resulted in the re-adoption of the .45 Colt, and eventually led the War Department to specify a minimum caliber of .45 for the new handgun. The prototype .41 caliber Colt automatic cartridge was never produced in production quantity, but the concept anticipated the development of the .40 S&W by over 90 years. Colt did produce a few "Model 1903" .41 cal. pistols, conversions of Model 1902 Military Models (the 1902 Military was an improved M1900/02), for the cartridge before the development of the cartridge ended.