VIDEO HERE (21:30 minutes)
In 1939 the government put out a tender for M1911A1 education contracts. These contracts were for production of just 500 pistols, and they were intended to pay a company to build the a complete set of production line tooling and then store it in case of future need (similar contracts were also issued for rifles and machine guns). Two companies were granted such contracts - Harrington & Richardson and the Singer Sewing Machine Company. Singer produced a quite satisfactory batch of pistols, but ended up making higher-priority material like artillery sights. H&R was unable to complete its contract, which was cancelled in the spring of 1942.
When the US entered the war, pistols were needed in large number, and three companies were given contracts to produce the M1911A1: Remington-Rand, Ithaca, and Union Switch & Signal. These three new contractors, along with existing production lines at Colt and Springfield, produced 1.9 million new pistols during World War Two, enough to fully supply all branches of the US military until 1985 when the 1911 was replaced by the Beretta 92.
The example we are looking at today is a Remington-Rand, manufactured in April 1945. Remington-Rand received its first contract in May 1942, and delivered its final pistols in July 1945. In total, it made 877,751, in the following serial number blocks:
916405 - 1041404
1279699 - 1441430
1471431 - 1609528
1743847 - 1816641
1890504 - 2075103
2164404 - 2244803
2380014 - 2619013 (the last one made was 2465139)