Which component is typically placed in the rim of the case in rimfire ammunition?

In rimfire ammunition, the primer is typically placed in the rim of the cartridge case. This design is a distinctive feature of rimfire cartridges, where the entire ignition mechanism is built into the rim. When the firing pin strikes the rim of the case, it crushes the primer, which then ignites the gunpowder within the cartridge, leading to the launch of the projectile. This design allows for a simpler and often less expensive method of ammunition construction compared to centerfire cartridges, which have their primers located in the center of the casing.

The other components mentioned, such as gunpowder and projectile, play crucial roles in the operation of the ammunition, but they are not located in the rim of the case. Gunpowder is the propellant inside the casing, and the projectile is the bullet that is expelled when the ammunition is fired. A wad is typically used in shotshells, not in rimfire cartridges.