sentences:  The Luger on the other hand would be developed at about the same pace as the Colt 1902, the competition peaking in 1907 when .45 ACP Colt 1905's and 45 ACP Lugers faced off, although in the end both pistols showed insufficient promise in the heavier caliber, and as the United States was committed to the .45 ACP, the basic 1902 design stayed terminally rooted to the .38 ACP and the Luger had a tad more stretch and would find the greatness with the 9 mm parabellum cartridge that would never come to the Colt 1900/1902/1905 series.However the Colt pistols helped sell the semi-automatic pistol concept in the United States and would contribute to the development of the Colt 1911.The M1902 was a short recoil operated pistol derived from the Model of 1900 by the simplification of its internal mechanism and a reduction in the number of internal parts.