Gun Glossary & Shooting Definitions

.177 (4.5 mm): The size of a pellet or BB as standard airgun caliber for national and international target shooting.

.22 Long Rifle: The size of a cartridge for standard .22 rimfire target rifle and pistol use.

.22 Short: The same size of a cartridge for standard .22 rimfire target rifles, but the case is shorter and fit to a 29 grain bullet.

.223 (5.56 mm): A centerfire cartridge with a bullet diameter of .224 inches and weighs 40-70 grains.

.38/357: A popular caliber introduced in 1935 by Smith & Wesson. The .357 cartridge case is .135 inch longer than the .38 case so as to distinguish between the two. The nominal bullet diameter of both is .357 inch and the standard bullet weights are 148 or 158 grains.

.41 Magnum: A centerfire pistol caliber with a higher velocity than the .44 magnum with lighter recoil it was introduced by Remington in 1964. The Bullet diameter is .410 inch and typical weights are 180 or 200 grains.

.44 Magnum: A centerfire pistol caliber with a bullet diameter is .429 inch and an average weight is 240 grains.

.45 ACP: A centerfire cartridge originally intended for military use with a bullet diameter that is normally .451 inch and average weight 230 grains.

7.62 (or 762 or .308): 7.62mm or .308in is the NATO standard machine gun cartridge caliber that shoots effectively up to 1200 yards. Bullets are .308 inch in diameter and range from about 110 to 200 grains.

9mm: A centerfire caliber used by the military in handguns, semi-automatic, and automatic guns. Bullet diameter is .354 with bullet weight about 115 grains and is often fired from .38/.357 guns.

Accidental discharge (AD): The unintentional firing of a gun, as opposed to a negligent discharge which is the unintentional firing of a gun due to misuse, mishandling, or irresponsible behavior while handling a firearm.

Accuracy: The measure of consistency in the performance of a firearm.

ACP: An acronym for Automatic Colt Pistol.

Action: The part of a gun that is loaded, unloaded, and fired. This part contains the breech-locking and firing mechanism, along with having the serial number.

Aim: The action of aligning the gun with a target in relation to the shooter's eye.

Aiming Mark: The part of a target in which a person attempts to hit, usually the center black circle on a piece of paper.

Aiming picture: (AKA Site Picture) A view of the site and the target together in the same view by the shooter or person aiming.

Airgun: Any rifle or pistol that uses compressed gas to propel a pellet or BB.

Ambidextrous Safety: A safety switch that can be operated by either hand because there is a switch on both sides of the gun.

Ammunition: The brand, type, and size of projectile used in a gun, including the gun powder and cartridge. Also refered to as ammo.

Aperture Sights: The type of sight that uses a small hole to centralize the shooter's eye, making it easier to align the front site post with the target.

Assault Weapon: A vague, emotional term used to instill fear into the ignorant by persons with political agenda. By U.S. Army definition, a selective-fire rifle chambered for a cartridge of intermediate power. This term is pejoratively assigned to any semi-automatic firearm simply because of its cosmetic appearance. This term is incorrectly used by politicians and the media on a regular basis.

Autoloading [Action]: A type of firearm that uses the recoil or expanding-gas energy to eject the spent shell and rechamber an additional shell. This action also prepares the firing pin for a manual pull of the trigger for the next shot, thereby repeating the process.

Automatic: A firearm designed to shoot continuously as long as the trigger is depressed and cartridges remain in the feed system.

Automatic Pistol: Often meant as semi-automatic pistol... a pistol that fires each time the trigger is pulled. People new to guns and shooting often confuse automatic and semi-automatic.

Automatic Safety: A catch on a break-open gun that resets to the "safe" position each time the gun is opened, usually via a limb attached to the top lever spindle.

Back Action: A sidelock action where the mainspring is mounted towards the butt of the gun. Often used in double rifles.

Backboring: Making the internal diameter of a shotgun barrel larger in an effort to reduce the recoil or to improve the shot pattern.

Balance: Describes the weight distribution of a firearm, particularly a break-open gun. If the balance is heavier toward the barrel it is slower to swing and slower to stop, but balance behind the break, more toward the stock, it is faster to swing and faster to stop.

Ball: Originally a round ball used in muskets or black powder guns. A smooth bored barrel that often meant inaccurate shooting.

Ballistic coefficient (BC): A measure of a given projectile's ability to overcome air resistance in flight.

Ballistics: The study of what happens to a bullet when a gun is fired, often requiring advanced mathematics and physics.

Barrel: The long tubular part of a gun that the bullet or pellets travel.

Barrel length: The distance from the muzzle to the chamber, but not including barrel extensions like flash suppressors or muzzle brakes. In handguns, the barrel length of a revolver, for example, is the distance from the muzzle to the breech end immediately in front of the cylinder.

BB: A) A small round ball used in "BB guns" or airguns, often .175 inch diameter. B) A round shotgun pellet of .181 inch in diameter. In most shotgun cartridges there are multiple BBs used for game such as pheasants, geese, rabbits, and others.

BDL, ADL: Remington grade designations: ADL is A Grade DeLuxe and BDL stands for B Grade DeLuxe.

Bench Rest: A platform for target shooting that enables a shooter to secure the firearm in a fixed or semi-fixed position for better accuracy.

Bipod: A device with two "legs" that can be affixed to a firearm or used to lay the firearm upon for a steadier shot.

Black Powder: The earliest type of firearms propellant, not typically used anymore. Ingredients: 3 parts potassium nitrate, 2 parts powdered charcoal, and 1 part sulphur.

Blank: A cartridge loaded without a bullet.

Blind Magazine: A rifle magazine that does not have a floorplate, but must be loaded from the top.

Blowback: A type of action in an autoloading firearm where the breech is not locked. Rather, the recoil of the firing cartridge overcomes the inertia of a spring-loaded breechblock, forcing it back to cycle the action.

Blow-Back: When a bolt is literally 'blown' open by the cartridge when the gun is fired.

Blue: Bluing is a thin surface coloring that forms a type of blue-black color. Bluing reduces the reflectivity and helps inhibit rust.

Boat Tail: A type of bullet that is tapered at the rear to increase accuracy.

Bolt: A cylindrical shaft used to lock in a cartridge in preparation of firing, often with an attached handle to manually load and reload the firearm. (Complete Bolt Carrier Group)

Bolt-Action: A gun mechanism used to manually unload and reload a cartridge.

Bolted Safety: A secondary safety designed to prevent accidental discharge on double-bolted rifles.

Bore: The inside of a firearm's barrel between the chamber and the muzzle.

Bore Diameter: The diameter of the insider of a barrel just ahead of the chamber.

Bore Line: An imaginary line projected from the muzzle of a gun along the center of the bore.

Bore Sight: The process of sighting-in a firearm, usually with the aid of a laser. The bore sight is placed within the chamber and sights are adjusted until the laser and the reticles hit the same target area. Laser bore sighting is meant only to help align a scopes reticles up to 25 yards.

Brass: A synonym for expended metallic cartridge cases.

Break-Action: A firearm design (double-barreled shotgun) that has a latch revolving about a hingepin that drops down to 45 degrees, exposing the breech for loading/unloading. An over-and-under shotgun is the most common type of gun with a break-action.

Breech: The end of a barrel, closest to the shooter, where the powder charge is ignited.

BSA: An acronym that stands for Birmingham Small Arms.

Bull: The center of a target, usually scoring 10 when hit. Bull's eye!

Bull Barrel: A large, heavy barrel used for target shooting or long-range varmint hunting.

Bullet: The name of just about any projectile expelled from a rifle or handgun.

Bullet Catcher: The part of shooting range which actually stops and retains the fired bullet.

Bullet Mold: A hand tool, generallt shaped like a pair of pliers, with a two-part cavity of specific dimension at the working end, into which molten lead is poured in order to cast a bullet for a specific firearm. Normally affixed with a sprue-cutter to trim the excess lead from the bullet.

Butt: The rear end of a rifle or shotgun stock that is placed against the shoulder. In a handgun, the butt is the bottom part of the handle. 

Caliber: The diameter of a projectile of a rifled firearm or the diameter between lands in a rifled barrel. (10 min Video of Caliber Basics by @hickok45)

Cap: An explosive device fitted over the nipple of a percussion black powder gun in order to initiate ignition of the main charge and fire the bullet.

Carbine: A rifle with a relatively short barrel.

Cartridge: A single, complete round of ammunition.

Cartridge Case: The case used to hold the primer, gun powder and bullet.

Center-Fire: A type of cartridge that has its primer located in the center. Thereby requiring a firing pin to strike the middle of the primer in order to fire.

CCW: Concealed Carry Weapon - The acronym for the permit that allows someone to carry a concealed firearm.

CDS: Custom Dial System. A system of customizing your Leupold rifle scope for all of the ballistic information for your gun, cartridge and atmospheric conditions. (How to Install a Leupold CDS Dial onto Your Rifle Scope)

Choke: A constriction or tightening of the diameter of the barrel to control the width of the shot group. A tight choke is used for further, more condensed shots on geese or turkey. Pheasants are usually hunted with improved or modified chokes.

Choke Tubes: A short piece of metal that screws into the barrel, tapering at different levels to affect shot dispersal.

Cleaning rod: Typically a piece of metal or plastic that is used to push or pull cleaning tools through a barrel. Cotton is often affixed to a cleaning rod to clean gun powder residue from the rifling of a barrel. Other metal brushes are screwed to the end of a cleaning rod as well.

Click: An adjustment, often to a rifle scope. A click is the smallest adjustment allowed.

Clip: An incorrect word used to describe a magazine.

Cock or Full-Cock: To set the action into position for firing a gun.

Comb: The upper part of the stock where the shooter's cheek rests during aiming.

Compensator: A muzzle brake designed to reduce the felt effects of recoil.

Crosshairs: Scope reticle: often 1 vertical line intersecting 1 horizontal line. (How to Zero a Riflescope)

Cylinder Gap: The small gap between the cylinder and the rear of the barrel of a revolver.

Cylinder: A) The part of a revolver (handgun) that holds cartridges in separate chambers B) A shotgun barrel with no choke constriction at the muzzle.

Double Action: An action type that involves pulling the trigger to both cock the hammer and fire the weapon.

Doubling: The accidental firing of two barrels of a double barreled gun, usually due to the recoil of the first shot, worn parts, or bad maintenance.

Drift: The lateral movement of a bullet due to either the rotation in flight or to wind.

Drop: The measurement of elevation drop from the exit of the bullet from the barrel to the point of impact.

Dry Fire: The intentional firing of an unloaded gun, usually for practice purposes.

Double Triggers: A trigger for each barrel on a double barreled shotgun (side by side or over/under).

Dummy Cartridge: Cartridges without propellant or primer for the use of safely testing firearms.

Dust Cover: A small piece of metal covering the ejection port of a firearm to prevent dirt, dust, mud, or any other foreign matter from entering the action or barrel.

Ejector: The mechanism that expels the cartridge or case from the breech of the gun.

Ejectors: A mechanism inside a double barrelled gun that lifts each cartridge enough to manually replace them or to eject them from the barrels while opening the break.

Elevation: Vertical sight movement so as to raise or lower the point of impact at the target.

Extractor: The device which extracts or removes the cartridge or cartridge case from the chamber of the gun.

Eye Dominance: All human beings have one eye that is dominant. Usually for right-handed people, it is the right eye. For left-handed people, it is the left eye. Eye dominance is extremely important since a person will never hit a target if they are using the wrong eye to aim at it.

Eye Piece: The lens of a sight, scope, binocular, or monocular nearest a person's eye.

Eye Relief: The distance between the shooter's eye and the rearmost part of the sight or scope.

F.P.S.: Feet Per Second.

Felt Recoil: The subjective experience of a shooter when they feel the recoil of shooting a gun. The felt recoil of a 12-gauge shotgun is different to a 15 year old boy than a 30 year old professional football lineman.

FFL: Federal Firearms [Dealer's] License.

Firearm: Any mechanism that uses a combustion to discharge a projectile.

Firing Pin: The part of a gun that strikes the primer of a cartridge. This primer strike sets off the charge of the propellant.

Flaking: When a gun's blued finish begins to fall (or flake) off.

Flash Suppressor: An attachment at the end of a barrel that reduces visible muzzle flash caused by the burning propellant.

Flintlock: A muzzle-loading firearm that fires by a flint striking a metal surface to produce sparks. This spark ignites fine priming powder which in turn sets off the main charge that fires the propellant.

Floated Barrel: A rifle barrel that is mounted firmly to the receiver but not touching the forend. A floated barrel helps to create a more accurate firearm since the barrel is not affected by the vibration of the stock.

Fluted Barrel: A rifle or pistol barrel that has longitudinal grooves milled within it to dissipate heat more rapidly.

Forend: The part of a gun that secures the barrel to the receiver.

Fouling: The carbon residue deposits that build up in the barrel of a gun after it is fired. If built up, the accuracy of the firearm will suffer.

Fouling Shot: The act of firing a gun for the sole purpose of removing oil or residue from a gun's barrel.

Full Metal Jacket (FMJ): A copper covering of a bullet that leaves no lead exposed.

Gain Twist: Type of rifling that increases (tightens) as the bullet approaches the end of the barrel.

Gape: The size of the opening space in a breech opened gun (e.g. double barrel shotgun)

Gas Vent: A vent built into a firearm to minimize damage to the gun and shooter when unexpected gas is created after the firing of a cartridge.

Gauge: The measurement of a shotgun's bore size that is determined by the number of round lead balls of bore diameter that equals a pound.

Glass Bedding: A process of adjusting a rifle's stock using epoxy that helps produce more accurate shooting. Glass bedding is a process undertaken to compensate for imperfect wood-to-metal fit.

Grain: A unit of weight equaling 1/7000 pound. This unit of measurement is used when measuring bullet weight. 150-grain bullets are common for whitetail deer hunting, 85-grain bullets are common for coyote hunting. Bear hunters usually load 220-grain bullets.

Grip: The handle of a gun stock held by the rear-most hand.

Grip Safety: A safety mechanism within the grip of a pistol used to prevent an accidental discharge. The safety is released when a person is properly holding the weapon.

Groove: The lowest part (valley) of a barrel's rifling.

Group: The pattern of shots on a target. A tight group means that all shots were very close to one another signaling accurate shooting. Group has nothing to do with accuracy of the gun. A tight group may be achieved several inches or feet from the intended target.

Gunpowder: An explosive combination of several chemicals including saltpeter, sulfur, and charcoal.

Hammer: The part of the action that strike the primer in a cartridge gun.

Handgun: A small, short-barreled firearm. 

Handloading: The process of DIY bullet-making. A person can handload shotgun shells almost any caliber of rifle cartridge.

Hang Fire: A long delay between firing a weapon and the ignition of the primer.

High-Capacity Magazine: A subjective determination of the amount of rounds held in a magazine. A made-up term by anti-second amendment advocates to indicate a magazine should have limits as to the number of rounds it holds.

Hollow Point (HP): A bullet type with a concave tip. This type of round tends to expand upon hitting its target. It is commonly used for self-defense and hunting.

Iron Sights: A combination of rear site and front site posts located on the firearm and used in concert by aligning both with the target. Adjustments can usually be made to either or both the front or rear site for desired accuracy.

Jacketed Bullet: Typically a lead bullet covered in copper, nickel, or steel.

Leading: A deposit of lead left inside the barrel of a gun from the passage of the bullet. The heat from the projectile leaves traces of lead in the rifling of a barrel and must be cleaned to maintain accuracy.

Lever-Action: A gun mechanism activated by manual operation of a lever. A .30-30 lever-action is most usually seen in western movies.

Load: A specific type of ammunition or cartridge.

Machine Gun: A large caliber, automatic weapon often used by the military.

Magazine: A spring-operated mechanism that holds cartridges for a semi-automatic gun. (How to load a magazine)

Magnum: A cartridge, rifle, or pistol that is loaded to higher than normal pressures.

Marksmanship: The ability of a person to consistently place shots at a desired point of impact.

Minute of Angle (MOA): The unit of measure used in adjusting rifle sights. 1.047 inches at 100 yards, 2 inches at 200 yards, and three inches at 300 yards.

Misfire: When the primer does not fire upon being struck by the firing pin.

Muzzle: The end of a gun barrel where a bullet exits.

Muzzle Blast: The blast felt by a shooter when they fire their weapon.

Muzzle Brake: A part of the barrel that traps and diverts gasses to reduce recoil.

Muzzle Energy/Velocity: The energy of a bullet when it leaves the barrel of a gun measured in foot/lbs.

Muzzle Flash: The flash seen at the end of a barrel after gun is fired.

Muzzle Jump/Climb: The vertical movement of the muzzle when then gun is fired.

Muzzleloader: The earliest type of gun used in the civil war. Technically any gun used where the powder and projectile is loaded through the barrel. Used today during a special season of deer hunting, typically.

Negligent Discharge (ND): The unintentional firing of a gun due to misuse, mishandling or irresponsible behavior while handling a firearm.

O/U or Over and Under: A double-barreled shotgun where each barrel is vertical instead of side-by-side.

Object Lens: The lens of a rifle scope closest to the shooter.

Offhand: Shooting while standing.

Open Sights: Same as Iron Sights. A combination of a rear site (v-shaped) and front site post located on the firearm. Used in concert by aligning both with the target. Adjustments can usually be made to either or both the front or rear site for desired accuracy.

Parallax: Shift in position between two separate and distinct points of view. If you have ever sat in the passenger seat of a car and looked at the speedometer, it looks like the needle is over the 45 mph indicator instead of the actual 50 mph indicator like it does to the driver. This is the shift in position described as parallax. (Learn more with our Guide on Parallax.)

Patch: A small piece of cotton or rag used to clean the inside of a barrel, typically.

Peep Sight: A type of iron sight that is mounted on the rear of a rifle that has an iron circle used to focus through on the front site post to the target. Also known as an aperture sight. The smaller the aperature, typically the more accurate. However, in low light conditions, a small aperature can make it impossible to shoot.

Pellet: A) Small projectiles loaded into and fired out of a shotgun shell. B) A small projectile designed to be fired from a pellet gun, often shaped to a point.

Pellet Gun: Any gun that uses compressed air to propel a BB or pellet.

Picatinny Rail: A specific type of bar designed to allow firearms accessories to attach to the gun with specific measurements and accuracy. (Shop Picatinny Rails)

Pistol: A firearm small enough to hold and be fired with one hand.

Pistol Grip: The type of grip that resembles a handgun grip but is placed on a shoulder-operated gun. (Shop AR15 Pistol Grips)

Point of Aim: The spot on your target where you are aiming to hit.

Point of Impact: The spot where the bullet or projectile actually hit in reality.

Primer: The ignition component of a cartridge.

Projectile: Any item coming out of the barrel of any type of gun when it is fired.

Pump: A type of action that requires a shooter to manually re-chamber a round by pulling back on the forearm grip. Most commonly used in shotguns and some .22 caliber rifles.

Pyrodex: A substitute for black powder that burns cleaner and more efficiently. Pyrodex is 100% man-made and is used most often because it is safer to handle, use and store.

Ramrod: A rod used to push a ball or bullet down the barrel of a muzzle loading gun. A ramrod cannot be made of any material that can cause a spark when scraping against the inside of a barrel. A spark could ignite the gunpowder and unintentionally fire the weapon. 

Range: Can be referred to as the the distance from the firing position to the target, or as a noun, any place where shooting practice takes place.

Range Officer: The person in charge of shooting on the range and usually also the safety officer.

Receiver: The part of a firearm with the serial number on it (lower receiver). This part holds the mechanical parts of the gun including the trigger housing and bolt carrier group. (How to Clean and Maintain an AR15 - Lower and Upper Receiver)

Recoil: The backward momentum of a gun when it is discharged, also known as "kick" or "kickback."

Recoil Pad: A soft piece of rubber than fits over rear end of the stock to inhibit damage or injury to a shooter's shoulder.

Release Trigger: A trigger that fires a weapon when the trigger is released, not when pulled. This type of trigger helps shooter that flinch too much for competition accuracy.

Reloading: (Handloading) DIY making your own bullets. The process of making your own bullets usually for customized accuracy or to save money.

Repeater/Repeating: A gun that can be fired multiple times with one loading. Repeaters are any gun that can load more than 1 bullet at a time that is manually rechambered. A lever action, bolt action, and pump shotgun can all be regarded as repeaters since you can load more than 1 round at a time and you manually reload each round.

Reticle: A network of fine lines or wires placed in the focus of the eyepiece of a rifle scope, telescope, or microscope that can be used as a measuring scale or an aid in locating objects.

Revolver: A handgun that stores cartridges in a cylinder. This cylinder rotates each time the trigger is pulled, thereby making the next bullet ready to be fired.

Rifle: A shoulder fired gun with a long rifled barrel, typically used for greater accuracy and longer distance shooting.

Rifling: Spiral grooves inside a barrel used to create a spin on a bullet. This spin causes the bullet to fly straight, much like a football is thrown with greater distance and accuracy when there is a spiral.

Rim: The oldest of all the types of cartridges - this type holds the cartridge at the proper depth in the chamber.

Rimfire: The method of firing a bullet that requires the firing pin of a gun to strike the cartridge rim, which ignites the primer - As opposed to centerfire, when the firing pin strikes the center of the cartridge.

Round: Synonym for a cartridge.

Sabot: Lead-cored, full copper jacketed projectiles used in a rifled shotgun barrels mainly for whitetail deer hunting.

Select Fire: Any type of gun that has a selector switch allowing the operator to alternate between semi-automatic firing and automatic firing.

Semi-Automatic: Any type of gun that requires a manual pull of the trigger for every round shot.

Shooting Sticks: An inexpensive device, often made of wood or plastic, used as a platform to balance a weapon in the aid of firing that weapon more accurately. 

Shot: Small, usually lead, balls or pellets used as a projectile for shotguns.

Shotgun: A shoulder gun usually with a smooth-bored barrel primarily intended for firing multiple small, round projectiles. Some shotguns have multiple barrels, like the double-barreled over-under or side-by-side. Some barrels also have rifling for better accuracy. These shotguns are used primarily for self-defense and white-tail deer hunting.

Shotshell: A shotshell is the official name for the type of cartridge required for a shotgun.

Sight: A) A device affixed to a gun that is used to help acquire or magnify a target. B) The process of adjusting iron sights or reticles on a shooting scope to create more accurate shots.

Sight Radius: The distance between the front and rear sights.

Sight Picture: (AKA Aiming Picture) A view of the site and the target together in the same view by the shooter or person aiming.

Silencer: A device that suppresses the sound of a firearm when fired. The reality is that there is no such thing as a mechanism that silences the firing of a bullet.

Single Action: A single action is when the hammer of a firearm only moves forward when the trigger is pulled. As opposed to double action where the hammer moves backwards first, then is released and moves forward.

Single-Shot: A gun that can only hold one cartridge at a time. It must be reloaded each time it is fired.

Skeet Shooting: The activity of shooting fast moving sporting clay targets with shotguns. Clay targets usually travel about 40 miles per hour.

Sling: A leather or synthetic strap used as an aid in carrying a rifle, shotgun, or muzzleloader.

Small-Bore: A description of a .22 caliber rifle, usually.

Smoothbore: Usually referring to a shotgun barrel or a type of gun with a barrel that is not rifled, but rather, completely smooth on the inside.

Spotting Scope: A high-powered optic used to locate game (for the most part) but also used at target shooting ranges to locate shot placement on a target. (How to Choose a Spotting Scope)

Stock: That part of a firearm that cradles the barrel that a shooter holds with their off-hand when firing. The term normally applies to rifles and shotguns but can also refer to the grips on a handgun. (Best Rated and Deals on AR15 Stocks)

Target: Any object that is used for the purposes of shooting, aiming, and improving shot placement.

Throat: The unrifled part of the bore immediately in front of the chamber.

Trajectory: The path followed by an object moving through space. In shooting, trajectory is the description of the flight path of a projectile relative to some known and fixed points. A typical trajectory of a bullet when it leaves the barrel is to rise slightly after 50-150 yards and then decline at a stead rate relative to humidity, wind, and gravity. There is a slight arc with all bullets fired from a gun.

Trap: Very similar to skeet shooting except clay pigeons are usually propelled up and moving away from a trap shooter.

Trigger: A device created to manually fire a gun.

Trigger Guard: A bow-shaped device circling a trigger to reduce the possibility of an accidental discharge.

Twist: The direction and tightness of a barrel's rifling. An M-16 A2 all the way through the M-16 A41 has a 1-7 twist, which means the bullet will rotate one time for every 7 inches traveled down the barrel.

Varmint Rifle: A rifle specifically designed for long-range shooting, often having a heavy barrel. Varmints hunted are usually prairie dogs, coyotes, crows, gophers, marmots, opossums, and skunks.

Velocity: The speed of a projectile after it has left the barrel, quoted in fps (feet per second).

Windage: The lateral sight adjustment so as to move the point of impact sideways on the target.

Zero: Zeroing is the process of aligning your point of aim with the point of impact, so that the two become one - under optimal conditions. (How to Zero a Riflescope)

Zoom: To magnify an object.