The cartridge was designed by John Browning for early blowback pistols that lacked a breech locking mechanism. The cartridge was designed to duplicate the performance of a .22 Long Rifle cartridge, when fired from a two-inch barrel. The .25 caliber was the smallest case Browning could use that still had space for a primer pocket. The greased, coated lead bullet design, standard for the .22 long rifle of the day, was replaced with a copper jacketed round nose profile for more reliable feeding in self-loading pistols. The bullet weight was typically 50 grains, keeping with the sectional density of the 40 grain .22 caliber bullet.