Remington Rand Research
Consequently some of the parts of the early Remington Rand pistols were made using Singer supplied tooling and fixtures. Careful examination of early Remington Rand pistols will reveal striking similarities in some of the parts to Singer made parts such as the triggers and mainspring housings. The first 255 production pistols where accepted by ordnance inspectors in November of 1942. Initial shipments appeared to perform satisfactorily, but subsequent tests performed by ordnance inspectors revealed serious problems with parts interchangeability. In March 1943 James Rand Jr. stopped production due to a high rate of parts interchangeability test failures. Only after a change in management and a thorough review of the inspection and manufacturing operations was production finally resumed in May of 1943. Throughout production Remington Rand aggressively attempted to innovate and improve the production of 1911A1 pistols.
By March of 1945 they where building the lowest price pistol in the war effort and quality was considered second to none. By the end of the war Remington Rand had produced over 875,000 pistols, almost as many as Colt (628,808) and Ithaca (335,467) combined. Reference: Charles Clawson, “Colt .45 Service pistols”.
I'm currently researching my Remington Rand on the 1911 Forum and at Harley Nolden's Institute For Firearms Research. It looks like the magazine is a General Shaver magazine, and correct for the gun. The General Shaver Division of Remington Rand manufactured magazines that were issued with Remington Rand pistols only and were fully blued, with a spot welded base marked with a " G " on the top of the lip of the base. The General Shaver magazines also had spot welding down the back of the tube.
The Colt barrel is curious. I'm wanting more information on that.
Remington Rand variation information is available here.