The .257 Roberts is a medium-powered .25 caliber cartridge. It has been described as the best compromise between the low recoil and flat trajectory of smaller calibers such as the .22 and 6mm, and the strong energy but not the strong recoil of larger popular hunting calibers, such as the 7mm family and the popular .30-06.
Many cartridge designers in the 1920s were creating various .25 caliber cartridges. Because of its size, the7×57mm Mauser case was a common choice, having near the ideal volume capacity for the “quarter-bore” (called this because the .25 caliber is one quarter of an inch) using powders available at that time. Ned Roberts is usually credited with being the designer for this cartridge idea. Eventually in 1934 Remington Arms chose to introduce their own commercial version of such a cartridge, and although it wasn’t the exact dimensions of the wildcat made by Roberts, they called it the .257 Roberts.
From its introduction until the appearance of more popular 6 mm cartridges such as .243 Winchester and 6mm Remington, it was a very popular general purpose cartridge. Today, although overshadowed by other cartridges, it lives on with bolt-action rifles being available from some major manufacturers.