This pistol is number 2 that was used for testing the Winchester Repeating Arms Company 45 caliber ammunition. The development was done in conjunction with Colt Fire Arms Company. The tests were conducted using 200, 230 and 255 grain bullets. The casings were brass and the bullets cylindro-spheric gilding jacketed. After the official introduction in 1905, Frankford Arsenal started to develop a slightly modified .45 cartridge with a longer case and heavier copper-nickel jacket bullet of 230 grains, named "Cal. .45 Automatic Pistol Ball Cartridge Model of 1906" (FA M1906) to be on time for the upcoming tests planned by the Government for June 1906. Remington UMC submitted 230 and 255 grain 45 caliber bullets for testing. In addition to the two-line caliber marking on the right side of the slide, the rear behind the serrations is marked with a decorative, intertwined "WRAC" and the right side of the frame is engraved "2of2 { Ctg. Test & Devlpmt 200 gr. 230 gr. 255 gr.}". The right side of the slide is marked with the two-block marking "PATENTED / APR. 20, 1897, SEPT. 9, 1902, DEC. 19, 1905." and "COLT'S PATENT FIRE ARMS MFG. CO. / HARTFORD, CONN. U.S.A.". The serial number appears on the left side of the frame and the left upper trigger guard bow is marked with the Colt triangle "VP" proof and the number "1" on the lower left rear. Standard fixed sights, blue finish including the barrel and unmarked magazine, niter blue trigger and casehardened hammer. Fitted with checkered walnut grips with diamond pattern around the screws.