EARS: Term used to refer to Hearing Protection. Usage on a range could be "Eyes and Ears Required," meaning Eye and Hearing Protection are mandatory. Ear protection must be warn at al times when shooting firearms to prevent hearing loss.
EJECTOR: Mechanical device used to eject empty cartridges from chamber(s).
EL PRESIDENTE: A standard exercise often used in training and sometimes used in matches. The shooter begins facing away from three targets with their gun holstered. On a signal from the range officer they turn, draw, and fire a double tap at each of the targets (for a total of six shots). The distance to the targets varies but it is usually 5 to 10 yards.
ELK FOUNDATION: Common name for the Rocky Mountain Elk Foundation or RMEF.
ENERGY: The capacity for doing work (transferring force). Spoken of in ballistics as Muzzle Energy or Remaining Energy. The measure of energy in ballistics is the Foot Pound. A projectile's capacity for doing work at a given range, expressed in foot-pounds.
ENGINE TURNING: Overlapped spots of circular polishing.
ENGLISH STOCK: A very straight, slender-gripped stock.
ENGLISH WEIGHTS & MEASURES: The basic unit of
weight in the English or British system is the grain which is based on the
weight of a grain of barley (Note: money was based on the grain of wheat -
and that three grains of barley weigh the same as four of wheat). This
grain is the troy grain - there is no other weight of the same name.
The weight of one grain is constant throughout the many different systems
of British weights. As you will see below, the ounce and pound are
anything but constant.
EROSION: The wearing away of the bore due to friction and/or gas cutting.
ETCHING: A method of decorating metal gun parts.
EXPANDING BULLET: One designed to increase in diameter on entering a target. Almost all rifle bullets intended for hunting are intended to expand on impact.
EXPLODING BULLET: A projectile containing an explosive component that acts on contact with the target. Seldom found and generally ineffective as such bullets lack the penetration necessary for defense or hunting.
EXPLOSIVE: Any substance (TNT, etc.) that, through chemical reaction, detonates or violently changes to gas with accompanying heat and pressure. Smokeless powder, by comparison, deflagrates (burns relatively slowly) and depends on its confinement in a guns cartridge case and chamber for its potential as a propellant to be realized.
EXTENDED MAG RELEASE: A magazine release that is larger or longer than normal. Typically found on competition guns, extended mag releases allow a shooter to more easily release the magazine with their strong hand while retrieving a fresh magazine with the weak hand during a speed or tactical reload. The use of Extended Magazine releases is limited or regulated in some of the shooting sports.
EXTENDED SLIDE RELEASE: A slide release that is larger than normal (usually protruding from the side of the gun) to allow for easier single hand operation. Extended slide release are often added to duty and competition pistols so the shooter can "thumb" the slide release with out changing the grip after a reload. On the AR-15 family of rifles the Extended Slide Release allows the shooter to release the bolt with the trigger finger.
EXTERNAL / EXTERIOR BALLISTICS: External or Exterior Ballistics is concerned with the motion of the projectile while in flight, and includes the study of the trajectory, or curved flight path, of the projectile.
For detailed information on External or Exterior Ballistics and related terms see the detail block below.
There is a lot of
misleading information and myth flying around ("bull-istics") on the
subject of the external ballistics of ammunition. The tables below will
hopefully shed some light on how that bullet really travels once you've
pulled the trigger. All tables are rounded to the nearest 10 feet per
second and drops are rounded to two places, unless I am trying to show
small increments. Greater precision is meaningless in the "real" world.
Even for the best of marksman a 1/2 minute of angle difference is
effectively meaningless at realistic ranges. The majority of information
is presented on rifle cartridges but the principles hold true for shotgun
and pistol as well.
Many people believe that
bullets fly in a straight line. This is untrue. They actually travel in a
parabolic trajectory or one that becomes more and more curved as range
increases and velocity drops off. The bullet actually starts to drop the
instant it leaves the firearm's muzzle. However, the centerline of the
bore is angled slightly upward in relation to the line of the sights
(which are above the bore) so that the projectile crosses the line of
sight on its way up (usually around 25 yards or so) and again on its way
down at what is called the zero range.
The most commonly used drag model is the G1 model (sometimes referred to--not really correctly--as C1) which is based on a flat-based blunt pointed bullet. The "standard" bullet used for this model has a ballistic coefficient of 1.0. A bullet that retains its velocity only half as well as the model has a ballistic coefficient of .5. The G1 model provides results close enough to the actual performance of most commercial bullets at moderate ranges (under about 500 yards) that it is commonly used for all commercial ballistics computation.
A Brief Discourse on Ballistic Coefficients
This is probably the best article I have read on ballistic coefficients. It was written by Jim Ristow of Recreational Software, Inc. and is reprinted here with his permission. It was designed to encourage a discussion about ballistic coefficients and to explain why good B.C.'s are crucial to getting accurate results from ballistic software. The illustrations were not part of the original article.
A Little History
In 1881 Krupp of Germany first accurately quantified the air drag influence on bullet travel by test firing large flat-based blunt-nosed bullets. Within a few years Mayevski had devised a mathematical model to forecast the trajectory of a bullet and then Ingalls published his famous tables using Mayevski's formulas and the Krupp data. In those days most bullet shapes were similar and airplanes or missiles did not exist. Ingalls defined the Ballistic Coefficient (B.C.) of a bullet as it's ability to overcome air resistance in flight indexed to Krupp's standard reference projectile. The work of Ingalls & Mayevski has been refined many times but it is still the foundation of small arms exterior ballistics including a reliance on B.C.'s.
middle of the last century (around 1945-1947) rifle bullets had become
more aerodynamic and there were better ways to measure air drag. After
WWII the U.S. Army's Ballistic Research Lab (BRL) conducted experiments
at their facility in Aberdeen, MD to remeasure the drag caused by air
resistance on different bullet shapes. They discovered air drag on
bullets increases substantially more just above the speed of sound than
previously understood and that different shapes had different velocity
erosion due to air drag. In 1965 Winchester-Western published several
bullet drag functions based on this early BRL research. The so-called
"G" functions for various shapes included an improved Ingalls model,
designated "G1". Even though the BRL had demonstrated modern bullets
would not parallel the flight of the "G1" standard projectile, the "G1"
drag model was adopted by the shooting industry and is still used to
generate most trajectory data and B.C.'s. Amazingly, the "G1" standard
projectile is close to the shape of the old blunt-nosed, flat-based
Krupp artillery round of 1881!
software is finally appearing based on methods used in aerospace with
drag models for different bullet shapes. Results are superior to
traditional "G1 fits everything" thinking, but now shooters must learn
B.C.'s are different for each model.
Coefficient of Drag for a bullet is simply an aerodynamic factor that
relates velocity erosion due to air drag to air density, cross-sectional
area, velocity and mass. A simpler way to view C.D.'s are as the
"generic indicator" of drag for any bullet of a particular shape.
Sectional Density is then used to relate these "generic" drag
coefficients to bullet size. The "Sectional Density" of a bullet is
simply it's weight multiplied by it's frontal area.
Coefficients are then just the ratio of velocity retardation due to air
drag (or C.D.) for a particular bullet to that of its larger 'G' Model
standard bullet. To relate the size of the bullet to that of the
standard projectile we simply divide the bullet's sectional density by
it's form factor.
B.C.'s are crucial to getting good data from your exterior ballistics
software. A good ballistic program should be able to use two velocities
and the distance between them to calculate an exact ballistic
coefficient for any of the common drag models.
EXTRACTOR: A device which partially lifts the spent casing(s) from the breech area, allowing the empty shell(s) to be removed and ejector buy the rearward motion of the slide or manually in the case of some shotguns.
EXTRINSIC SAFETY DEVICE: These are safety devices with are added externally to the handgun, or provide a mechanism for storing or securing it. In order to fire the gun, the device must be physically removed from the gun, or the gun must be removed from the device. Examples include, trigger locks, barrel locks, gun safes and lock boxes.
EYE DOMINANCE: In reference to the shooters dominant or aiming eye. It is most common to be right-handed and right-eyed, or left-handed and left-eyed, but it is not unheard of to be cross-dominant as well. To determine eye dominance, extend you arm and hold up one finger, with both eyes open, focus on the finger tip and slowly bring you hand back until your finger tip lines up with your focusing or dominant eye. For more information see Cross-Dominant.
EYES: Term used to refer to Eye Protection or Shooters Safety Glasses. Usage on a range could be "Eyes and Ears mandatory." Meaning eye and ear protection are required. It is unsafe to use firearms, even outdoors, without proper eye and ear protection. Failure to use appropriate protection can result in permanent injury including blindness and hearing loss or impairment. Commercial products are available which in various styles and price range at your local range or gun shop.