As related by the included factory letter, this pistol was part of a short 7-piece run made by Colt to the specifications of the United States Marine Corps. Delivered to the Corps in 2003, an unspecified number were then returned to Colt in 2004, and stayed in the Colt Engineering Archive Collection as a historical/engineering reference until 2016, when it was released via a special sale exclusively for Colt employees. Between the mid-1980s and the mid 2000s, USMC elements like Force Recon were armed with the M45 pistol, a vintage U.S. 1911/1911A1 pistol heavily upgraded by the USMC Precision Weapons Section to then-state of the art, often with little left of the original handgun save the frame. The process for making the M45 was time and labor intensive, and the Corps began soliciting designs from outside firms, including Springfield Armory (Inc) and others. Outside sources became more important about 2005, when after about 2 decades of resistance the Corps established the Marine Corps Forces Special Operations Command (MARSOC) as a component of the United States Special Operations Command (SOCOM), creating a new component of the Corps with a need for a large caliber handgun. These searches would eventually culminate in the acceptance of the M45A1, a military-specific model of the Colt Rail Gun, which could be seen as a descendant of these prototypes. The heart of the OUSMC pistol is a Colt Series 70 Government Model 45 ACP, and the most prominent upgrade is the addition of a welded-on MIL-STD 1913 Picatinny rail on the dust cover, in addition to a Commander-style skeleton hammer, beavertail safety with speed bump, flat checkered mainspring housing, wrap-around checkered rubber grips, lightly funneled magazine well and a Wilson Combat magazine. "USMC" has been engraved into the left side of the slide, with "UNITED STATES PROPERTY" on the frame and a set of blanked-out medallions on the grips. The barrel is marked "PM" on the lug and hand-marked "AI" to match a similar marking on the underside of the slide, with a peened-in linkage pin and an interesting two-stage throat bevel. The rail has four slots, with a groove down the center for wiring, and is secured with a set of six weld points applied through three drilled holes in the dust cover; the attachment is permanent and rock solid. In addition to the factory letter, the pistol comes with a shipping document from Marine Corps Systems Command at Quantico to Colt (identifying the contents as a "1911A1 PISTOL") and a Colt blue plastic case numbered to match the pistol with a "MODEL-OUSMC" and "USMC PISTOL" label.