Ram - The main plunger or shaft of a metallic ammunition reloading tool.


Range - 1. A place where shooting is conducted. 2. The horizontal distance of travel of a projectile from gun to target.


Ream - To remove metal from a cavity with a rotary cutting tool.


Rebated Rim - In cartridge case design, a case whose rim is smaller than the body. Examples: 284 Winchester and 50 Action Express.


Recoil - The backward thrust or "kick" of a gun caused by the powder gases pushing the bullet through the bore and the jet effect of the gases themselves.


Recoil Buffer - A cushioning device to help reduce action battering; most commonly used in semi-automatic firearms.


Reloading Press - A tool used in reloading ammunition. Usually has some form of mechanical advantage to reduce effort in resizing or reforming cases. Available in several basic types known by the shape of letters of the alphabet; "O" types are most common today, but "H" and "C" types have been used also.


Remaining Energy - The residual or "down-range" energy of a projectile, measured in foot pounds, at a given distance from the muzzle.


Remaining Velocity - The residual speed of a projectile at a given point on its trajectory.


Reticle - The aiming indicator at the focus of a telescopic sight. May consist of straight or tapered lines (crosshairs), dots, posts, or some combination thereof. Some scopes have auxiliary marks for range estimation.


Rifling - Spiral grooves cut or impressed into the bore of rifles and pistols in order to make the bullets spin, insuring stable flight to the target. See grooves and lands.

 
Rim - The feature at the base of most cartridge cases in which the extractor engages to pull a fired cartridge from the chamber. In England this is called the flange. See rimless and rimmed.


Rimfire (RF) - Cartridges which contain the priming mixture within the rim. This type is not reloadable under any practical conditions.


Rimless - A case head type; actually a misnomer. Rimless cases have a rim, but it is the same diameter as the case body so it does not protrude. An undercut extraction cannelure or groove provide a surface for the extractor to grip. Example: 30-06 Springfield


Rimmed - A case head type whose rim protrudes beyond the case body. Example: 30-30 Winchester.


Round - A military term meaning one complete cartridge.


Round Nose - Bullet design feature; a blunt, spherical nose shape.


Rupture - Also separation. In shooting, a failure or break in the wall of a cartridge case, usually allowing gas to escape.