Remington Rand did not manufacture all of its own parts. They famously sourced frames and slides from other companies. This is a key authentication point.
The slide markings changed over time as the company simplified its production process. Collectors categorize these into three distinct types: serial number remington rand 1911 markings
As a renowned expert on 1911-pattern pistols, Jack knew that Remington Rand was one of the contractors that produced the M1911 during World War II. However, the presence of the marking, in addition to the standard military acceptance stamps, piqued his curiosity. Remington Rand did not manufacture all of its own parts