This is a excellent example of the Colt Model SSP Automatic Pistol. Only a handful of these SSP models were ever actually made (estimated at somewhere around 30-50 pistols total) by the Colt company in response to the Department of Defense solicitation for a new service pistol to replace the Model 1911A1 .45 Automatic. The original Colt Model 1971, as it was called, was designed and developed by the Research and Development Department of Colt Industries just prior to 1971/72 time frame and displayed some very unique features; namely it had a double stacked magazine, hammer blocked safety; single and double action mechanism, and a stainless steel slide and frame and of course was chambered in the old stand by of 45 ACP. Colt's intentions with this pistol were actually two fold; one for it to be the next evolution of the famous Model 1911A1 pistol, with new updated features, like the double action mechanism intended to help Colt's sagging sales on the US commercial market, second to compete for any future U.S. or Foreign Government military contract sales, as well as any other World Wide Commercial sales against any other company. The "Model 1971 Double Action" pistol nomenclature continued for several years until the late 1970s, where it was changed to the "SSP" (Stainless Steel Pistol) when the U.S. Government announced its intentions to replace the Model 1911A1 Service Automatic. A similar version of this SSP handgun (only in 9mm) was submitted by the Colt Company on two different occasions to the U.S. Government for testing and evaluation against the New XM9 Performance Specification requirements. The first time was in early 1980 and the second time was in early 1984. It was during the second series of tests that the Beretta 92F pistol won out over the Colt SSP and was selected to become the new Model 9, 9mm military handgun. Each one of these pistols regardless of the caliber was virtually handmade. It is estimated that less than 50 total pistols were produced with this one in the old reliable 45 ACP cartridge. This pistol is marked on the right side of the left side of the slide; "COLT'S MODEL SSP/45 ACP." and the right side of the frame is marked with "COLT'S PT.FA. MFG.CO. HARTFORD. CONN. U.S.A." over serial number GX9758" and it has the Colt checkered walnut grips with the silver medallions at the top. It was manufactured with a stainless steel slide and frame that retains the milled and matted/bead blast contracting metal surface. Several of these SSP were given away to top ranking members of the military to curry favors after the competition such as Gen Curtis LeMay. Certainly would be worth doing some additional research on this specific pistol.