Utah, the 725 was a higher grade of 721 and 722 but was not of the same design of the 720.
The 720 was a modernized Model 30, both descended from the P17 Enfield. The 721/722/725 were fresh designs and forerunners of the M700.
Wikipedia actually has a nice history...
"Prior to World War II, the Remington Model 30, had been the standard Remington bolt action sporting rifle. However production had halted during World War II.
During the war, Remington gained experience manufacturing large quantities of martial firearms more efficiently. By the end of the war, manufacturing technology had advanced significantly. By these standards, older designs like the Model 30 (and the Model 720 variant) were laborious and expensive to produce and could not take advantage of manufacturing advancements.
The Mauser M 98 action was popularly recognized as being well suited to sporting rifle applications but was complex and would require design changes to better take advantage of modern production techniques.
Rather than continue manufacturing older rifles that had become expensive to produce, Remington chose to develop an altogether new and modern rifle design with Mike Walker and Homer Young playing key roles. These factors converged in the development of the Remington Model 721 / 722.
The new Model 721/722 was introduced in 1948. Deluxe versions became available in 1955. The Model 725 variant was later introduced in 1958. These models all share a common design only differing by features and may be collectively referred to within this article as the Model 721 unless otherwise noted. Model 721 production ended in 1961 with the replacement Model 700 taking over in 1962. The Model 700 was also designed by Mike Walker and largely continues the 721 design with modern aesthetic improvements."
