Terms that start with R

Recoil is the backward kick of a gun that occurs when the gun is fired.

A reticle, also known as a crosshair, is a superimposed shape or image that helps shooters get accurate alignment when using a scope.

Rimfire refers to a type of firearm cartridge. This particular cartridge is referred to as rimfire because its pin strikes the base of the rifle cartridge's rim in order to ignite it.