The following information was provided by Malcolm MacPherson & the Remington Company Historian.
After WWI Remington modified post-war surplus into non-firing training rifles since the 1903 Springfield rifles were in short supply. The barrels were cut to the dimensions of the US Model 1903 Springfield rifle. These rifles are commonly found with a month/year date code but no serial number. The Cadet rifle was sold to private military institutions. Unfortunately there is no production information about these models”.
The original barrel length of the Model 91 Mosin Nagant was 31.6 inches and the 1903 Springfield barrel length was 24 inches. This results in 7.6 inches being removed from the barrel. The forend of the stock was also shortened. The barrels on these Cadet Trainers had no front sight. It is unknown what other modifications that Remington used to prevent these rifles from being fired. These models had a functional bolt so I suspect that the firing pin was shortened.
During this same time period Bannerman sold a similar modification. These can be identified by the fact that they carry a serial number as they were converted Russian military rifles. The front barrel band on the Bannerman model may be from a different military firearm.
I picked this one up about a couple of years ago and have since seen 12 posted on other forums with the rack number stamped into the stock in the identical location, these slightly differ from most as they do not have the M1917 nose caps installed on the stocks by the Bannerman Co