The .25-25 Stevens was an American centerfire rifle cartridge. Designed by Capt. W. L. Carpenter, 9th U.S. Infantry, in 1895, the .25-25 Stevens was the company's first straight-cased cartridge. It was used in Stevens' single shot Model 44, as well as the Model 44 1/2 rifles, 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 also suffered a "freakish" appearance, due to its length to diameter ratio. It was also found that the usual 20 or black powder charge of the shorter 25-21 offered "practically the same ballistics" as 24 or in the .25-25. The switch to smokeless powder only exacerbated the problem, due to the small charge. To cure this, handloaders use a mix of 3 to 5 gr of bulk shotgun powder and 18 to 20 gr of black powder, with bullets of between 60 and 86 gr. The bore diameter of the .25-25 Stevens is .250 inches (6.35 mm) making it a ".25"/6.35 mm caliber" cartridge, not to be confused with the more well known 6.5 mm bore caliber which uses 6.7 mm/.264" bullets.

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