An older design for ammunition in which the primer is distributed around a rim, protruding outwardly around the case head (See Case). This design is restricted to the lower pressures of earlier blackpowder ammunition in use before the invention of modern smokeless powder in the 1890s. Other than historical ammunition, rimfire is relegated now to .22 rimfire. This is the traditional “.22” of popular reference whose most common variant is .22 Long Rifle (LR). It propels bullets at velocities less than 1000 feet per second, or subsonic.
