The .25-21 Stevens is an obsolete and discontinued American centerfire rifle cartridge.
Designed by Capt. W. L. Carpenter, 9th U.S. Infantry, in 1897, the .25-21 was based on the longer .25-25. It was Stevens' second straight-cased cartridge (after the .25-25)Barnes, p.75, ".25-25 Stevens". and would be used in the single shot Model 44 rifle, as well as the Model , which first went on sale in 1903. In addition, it was available in the Remington-Hepburn target rifle.
While the .25-25 was popular, the .25-21 offered "practically the same performance and was a little cleaner shooting." It was also found the usual black powder charge of the shorter, bottlenecked .25-21 offered "practically the same ballistics" as in the .25-25. It was highly accurate, reputedly capable of generating groups at .
In power, the .25-21 was outpaced by the .25-20 WinchesterBarnes, p.20, ".25-20 WCF". and .32-20 Winchester,Barnes, p.46, ".32-20 Winchester". while today, even modern pistol rounds such as the .38 Super offer superior performance.Barnes, p.164, ".38 Colt Super Automatic".
Notes
Sources Barnes, Frank C., ed. by John T. Amber. ".25-21 Stevens", in Cartridges of the World, pp. 74 & 123. Northfield, IL: DBI Books, 1972. . ______ and _____. ".25-25 Stevens", in Cartridges of the World, p. 75. Northfield, IL: DBI Books, 1972. . ______ and _____. ".25-20 WCF", in Cartridges of the World, p. 20. Northfield, IL: DBI Books, 1972. . ______ and _____. ".32-20 Winchester", in Cartridges of the World, p. 46. Northfield, IL: DBI Books, 1972. . ______ and _____. ".38 Colt Super Automatic", in Cartridges of the World, p. 46. Northfield, IL: DBI Books, 1972. .