Action Job - A reference to a modification or enhancement of a firearmís moving parts in order to make them function more smoothly and reliably. It usually involves fitting moving parts to a much higher standard than that done at the factory, the flattening and polishing of uneven edges or surfaces on metal parts. Action jobs also may include the replacement of springs in the firearm with improved springs or springs best suited for particular types of ammunition. An action job may also entail an alteration to the functioning of a gun, usually a handgun as in the conversion of a conventional double/single action handgun to double action only. This has been a common practice among police departments that consider single action guns to be unsafe.

Action types -

Single shot,

rifles, shotguns,


The gun has no magazine and must be loaded one shot at a time. A hammer or similar mechanism must usually be reset every time the gun is fired. Some single shot guns are recocked when the action or breechblock is manually opened or closed for loading or reloading.

Double barrel (shotgun or rifle)

Drillings (combination rifle & shotgun)

Derringers (handgun)

These guns have more than one barrel and chamber built into the same action that opens and is reloaded by means of a hinge mechanism. The gun has no magazine connected to the action and cartridges must be inserted into the chambers by hand. The gun may internally cock on opening and or closing, or manually by an external hammer or knob.

Black powder guns of this type do not have the hinge mechanism for reloading but are reloaded from the muzzles of the barrels.


rifles, shotguns, some handguns

Repeaters have a hammer/ trigger / safety function that is similar to a single action automatic, but some manual action must be done in order to activate the bolt or slide mechanism. The manual cocking / chambering action is done by the shooter for every shot by manipulating a lever, bolt or slide of some type to load a cartridge from the gunís magazine. Most common repeaters are lever action rifles and "pump" shotguns.

Bolt action

rifles, shotguns, some handguns

The gun is internally cocked when the bolt is manually opened or closed by the user. Bolt actions may be repeaters or single shots, depending on whether or not they have a magazine.

Single action (revolver)

The gun has a cylinder that holds five or more shots (usually six). The hammer must be manually set (cocked) for each shot or the gun will not fire when the trigger is pulled. The trigger only releases the hammer when it is pulled and serves no other purpose (only one action is performed by the trigger).

Nearly all black powder revolvers are single action. The cylinders are reloaded by means of a miniature press mechanism built into the frame of the gun.

Double action


The gun has a cylinder that holds five or more shots (usually six) but the cylinder is faster to reload because it swings out on a pivotal arm. The hammer may be pulled back in order to rotate the cylinder and cock the gun like with a single action or the user may pull the trigger to cock and fire the gun in one motion. Since the trigger can both cock and fire the gun, this action is called double action.

The double action trigger pull is both longer and harder than the single action pull because the user must overcome the force of the hammer spring when pulling the trigger. Pre-cocking a double action handgun negates the necessity to overcome the hammer spring with the trigger finger, thus the trigger has a shorter distance to travel and the pull is lighter when the gun is fired single action. Some double action revolvers are made to fire double action only (DAO) since some people regard the light single action trigger pull to be a safety hazard.

Single action auto or semi-automatic handguns, rifles and shotguns, selectively available on most full automatics

The trigger action is very similar to the single action revolver but the hammer is usually cocked when the slide or bolt is pulled back and a cartridge is taken by the mechanism from the magazine to the firing chamber. The gun recocks itself every time it is fired as the slide or bolt automatically travels back to load another cartridge into the firing chamber and recock the gun. The trigger must be pulled again in order to fire the gun and recock the gun and reload the chamber.

Single action automatic handguns may often be decocked in a number of ways, and must be recocked in order to fire if one has been decocked. Only the hammer must be manually pulled back in order to recock the gun if it has been decocked. These types of guns usually have a safety lever that prevents the cocked gun from firing if the trigger is pulled while the safety is engaged (called "on safe").

Double action auto

semi-automatic handguns only

The action combines elements of the single action automatic and the double action revolver. The gun functions as a single action automatic for initial loading and cocking. When the gun is decocked, the user may both cock and fire the gun by pulling the trigger.

The double action trigger pull is stiffer and longer than the single action trigger pull for the same reasons as with the double action revolver. A double action automatic will function as a single action automatic for every shot that the slide automatically cocks and the user does not manually decock, meaning that it is usually double action on the first shot and single action for the rest.

Many double action automatics will have a safety mechanism that both decocks the gun and disengages the trigger so that the trigger may be pulled, but the gun will not fire if the safety is engaged. Other guns may have a single action style safety that does not decock the gun but will still block or disengage the trigger. Some models have only a decocking lever that decocks the gun but leaves it ready to fire if the trigger is pulled double action style.

Some newer models are double action only (DAO) and frequently do not have safety or decocking levers. DAO automatics do not cock themselves when the slide travels rearward, manually or automatically. The hammer only cocks when the trigger is pulled, each shot fires DA (trigger cocks and releases the hammer).

Full automatic

rifles, shotguns, handguns, assault rifles, machine-guns, submachineguns

The gun functions like a single action automatic but the gun continues to cock and fire itself fully automatically when the trigger is pulled and held back until the gun runs out of ammunition or the user lets up on the trigger.

Selective fire

rifles, shotguns, handguns, assault rifles, machine-guns, submachineguns

Combines features of a semi-automatic and full automatic firearm by means of a selector lever or switch that usually acts as a safety mechanism. The user has the option of making the gun fire as a semi-automatic or full automatic by means of manipulating a lever or switch on the gun itself. Some modern military guns have this feature built directly into the trigger mechanism and have a separate safety switch.

Burst fire

assault rifles, submachineguns, handguns

MP5A3, M16A2, Beretta 93R

A feature found on some modern military and police guns that allows the user to fire the gun fully automatically for a set number of shots and then the gun will stop firing and the trigger must be released and pulled again in order to fire another burst. Most burst fire guns have a selector lever similar to that of the select fire gun but also include an internal ratchet mechanism that limits the number of "full automatic" shots to three at a time.

Assault case - A zippered nylon or canvas gun case that incorporates accessory pockets, a sling, and ammunition pockets. Most are lined with foam padding that will allow the case to float in water. These cases are intended for use "in the field" to protect the gun from the elements and carry relevant accessories in a minimum of space with a maximum convenience. These cases are favored by law enforcement personnel.

Assault Rifle - A rifle that fires an intermediate powered rifle cartridge from a detachable magazine either semi-automatically (one shot with each pull of the trigger) or fully automatic (the gun fires shot after shot while the trigger is held back and stops firing when the trigger is released or the magazine runs empty).  Assault rifles are commonly used by military organizations. "Assault Rifle" Translated from German Sturmguvwer (Storm Rifle). The first known assault rifle was the German Stg 44, which was developed toward the end of W.W.II as an alternative weapon for assault troops who needed features of both the rifle and the submachinegun in one weapon. The concept was adopted by the Russians and used in the AK-47 assault rifle which became the most common military rifle design in the world. Most assault rifles on the civilian market are not capable of full automatic fire.

Assault Weapon - A legal term used to define automatic and semi-automatic firearms that have features analogous to post W.W.II military small arms. The term is an issue of much legal and social debate. In most cases, assault weapons have a general design that follows that of a military rifle or submachinegun and may have some degree of parts interchangeability with military weapons. Assault weapons may have any combination of two or more of the following: a large capacity detachable magazine, a folding stock, a flash hider, a bayonet mount, a pistol grip separate from the stock, and or a folding bipod attached to the gun. Some shotguns qualify as assault weapons if they have the same features described above.

Assault pistol - A term that usually refers to a handgun that is semi-automatic and or full automatic, is larger and heavier than most other handguns, and may have features analogous to assault weapons. Many assault pistols have a magazine well that is in front of, rather than inside, the pistol grip (HK SP89, Tec-9) although many assault pistols, the UZI pistol, and M 11/9 for example, do not. Assault pistols generally take a high capacity magazine and are similar in design to compact submachineguns. 

Assault Shotgun - Usually a semi-automatic shotgun with features analogous to assault weapons, although some rare full automatic assault shotguns are known to exist. Some legal definitions include repeating shotguns that have "assault" features like large capacity magazines or folding stocks. Military assault shotguns generally are selective fire and have detachable magazines. An example would be the USAS-12.

AK-47, AKM, AK Series - Translates from Russian acronym meaning "automatic rifle by Kalachnikov of 1947" Avtomat Kalachnikova (of) 1947. The model designations of a military rifle originally designed by Mikhail Kalachnikov for the USSR and adopted by almost all Communist countries in the cold war. The general design has underwent several refinements (usually for the benefit of the manufacturer rather than the user) but has generally remained the same since 1947. Several variations are made by several different manufacturers under different names and acronyms. Most versions sold in the U.S. are not capable of full automatic fire.

AK type, AK style or AK Pattern - i.e. This gun takes an AK style magazine. A reference to a design attribute that is analogous to the AK-47 rifle or one of its components.

Ammunition - The components of a projectile weapon that are used up and or consumed in the process of launching a projectile. The projectile itself is a component of the ammunition. Rifle cartridges, bazooka rockets, slingshot pellets and catapult rocks are all examples of ammunition.

AR15, AR-15, AR Series- Acronym of "Armalite Rifle Model 15". The model designations of a rifle designed by Eugene Stoner of Armalite and manufactured by companies associated with the primary military contractor of the U.S. military M-16 rifle.  All of the companies incorporated with the trade name Colt in their title and have been located in Hartford, Connecticut, as the original Colt corporation has been bankrupted several times and the trademark and facilities sold several times. Since the original Colt company did not hold a patent on the design of the gun, several parts makers and other military contractors sold parts and eventually complete guns of very similar design. This rifle shares several major features with the military contract M-16, but is not normally full automatic, thus the AR-15 was the semi-automatic civilian version of the M-16 rifle made for the military. Original AR-15 rifles have been out of production for civilian sales since 1991 but are made available to police agencies. Several nearly identical guns have been made by other companies under other names but are most frequently referred to as AR-15s as a common slang term in reference to the general design of the gun. Generally speaking, there is a high degree of parts interchangeability from gun to gun and manufacturer to manufacturer.

AR Style or AR type or AR pattern - i.e. This gun takes an AR style magazine. A reference to a design attribute that is analogous to the AR-15 rifle or one of its components.

Auto Sear - A reference to a key part in a full automatic gun that is missing in a semi-automatic gun and must be installed along with other parts for a proper conversion to full automatic or select fire.  i.e. The auto sear will fit the early Colt but not the later models.

Blooper - A military slang term referring to 40mm grenade launchers first used by U.S. servicemen in the Vietnam conflict. Some people use this term in reference to any similar handheld or rifle mounted grenade launcher that fires a cartridge style grenade.

Bull Barrel, Heavy Barrel - A reference to a gun barrel that is thicker and heavier than standard barrels in that caliber or type of gun. Bull barrels tend to be slightly more accurate and less prone to bending or vibration than standard or lightweight barrels. They are usually found on guns built or modified for enhanced accuracy and or resistance to overheating during repetitive fire.

Bullet hose - Gun slang, any automatic weapon that is built for utility and reliability rather than refined accuracy.

Bullet trap - An apparatus used on shooting ranges to catch bullets after they have passed through or by their intended targets.

Bullet trap grenade - A European pattern rifle grenade that is made to be launched from the end of a rifle using standard ammunition. The grenade traps the bullet and "hitches a ride" to the target. They are not widely used because of safety concerns.

Buckskinners - A reference to the cultural identity of persons associated with the preservation of the practices and lifestyles of early to mid-19th century American and Canadian pioneers. "Mountain Man Rendezvous" are gatherings that are held and attended by Buckskinners in all parts of North America. They generally seek to accurately emulate the wilderness survival methods of early American pioneers and use similar equipment. True Buckskinners disdain any equipment that uses technology more advanced than that found in 1849. Many Buckskinners become proficient in the manufacture of replica primitive weapons and ammunition, including black powder arms and ammunition.

Burp Gun - A slang term referring originally to the Russian PPSH 41 which was a submachine gun that had an unusually high rate of fire. The noise of the gun was likened to a long, loud burp by people who encountered it. The slang term eventually grew to include any gun that had a high cyclic rate and made a similar noise.

Cash and Carry - A slang term referring to a transaction between a buyer and seller where the buyer pays cash for and immediately receives the merchandise from the seller. No further delay is involved in the transaction. Commonly a catch phrase used to negotiate terms of a transaction at gun shows. 

COD - Acronym for Cash On Delivery. A payment method common to mail order and phone order sellers who send merchandise via a common carrier (like UPS) before the merchandise is paid for. The receiver (customer) is expected to pay for the merchandise immediately with cash when the common carrier delivers the merchandise. The common carrier then pays the seller by certified check on a predetermined basis (usually monthly).

CCW - Acronym for Carry Concealed Weapon. A reference to a permit or license that is issued by a government body (usually a law enforcement agency) to private citizens which allows them to legally carry concealed weapons (usually a handgun).

Clip - A device that holds ammunition, usually cartridges for firearms. Clips are usually made from metal or plastic and do not have moving parts. Slang term for detachable magazine, usually associated with handgun magazines and improperly used to refer to detachable rifle magazines. See also Magazine

Grease Gun - A term originally referring to the U.S. M3 submachine gun first used in W.W.II. The gun was simple and cheap and had a passing resemblance to a tool used by mechanics to lubricate machines and parts of motor vehicles. The term has grown in some law enforcement circles to include any crudely designed or made submachinegun.

Junk Gun - A term usually referring to small, cheap, low quality handguns commonly used by criminals.  These guns have been the target of restrictive legislation and product liability lawsuits against manufacturers. Experts disagree on exactly what makes a gun a "junk gun".  It can also mean an older worn out or nearly worn out gun of any type. 

Magazine - The part or a repeating firearm that holds ammunition that is ready to fire. May be integral (built in) to the gun or detachable. A magazine differs from a clip in that it usually has moving parts.

Militia - An armed organization made up of mostly volunteer non-professional soldiers, usually formed to defend a geographic area or community from outside armed aggression. Militias usually use military style weapons, equipment and tactics. Small arms and personal equipment are usually provided by militia members or their families. Militias may follow a military-like command structure if they are associated with or funded by a government body. More commonly, militias are only quasi-military in organization, usually led by leaders who are chosen by informal democratic methods rather than being appointed by higher authority. Task distribution and authority are usually determined by job title rather than a oneís position in a hierarchy. A classic example would be the Lebanese militias of the 1980s.  Militias are generally led by charismatic individuals who have some formal military training. 

Parts kit - A collection of parts from or for a particular gun. Commonly retrieved from military scrap or surplus weapons. Usually missing some key part that must be manufactured or purchased through regulated channels. Many parts kits are compiled of new unused parts that are bundled together and sold at a discount by parts manufacturers for the rebuild or construction of new guns by private parties and firearms manufacturers. Parts kits are rarely backed by any warranty or liability coverage.  Unlike motor vehicles, many guns are cheaper if purchased in their component parts and assembled by the end user. 

Posse - Similar to a militia, a posse is an armed group of individual non-professionals formed to assist in the enforcement of law.  Posses generally are led by sworn law enforcement officials and are active in rural areas.  They are usually commissioned by a local sheriff for a limited time to complete a determined task.  While the militia serves seeks military objectives, a posse is generally limited to law enforcement tasks.  Modern posses also act as auxiliaries to county agencies in emergencies - usually in search and rescue efforts.  Also - slang term referring to a small gang, usually black or Hispanic in origin although such gangs may include white or Asian members.

Speed Rig - A type of holster and belt combination that is engineered to allow the wearer to quickly remove a handgun from the holster with little effort. Commonly used by gunfighters in the old west, and modern IPSC and PPC competitive combat sport shooters. Modern speed rigs make extensive use of springs and clips, rather than straps or snaps to retain the handgun. Some SWAT personnel use speed rigs for their handguns.

Starlight, Starlight Scope - A high quality electronic night vision device that uses existing light, even ultraviolet or infrared starlight, to allow the user to see at night. The U.S. Military uses starlight scopes extensively. The technology is also used in electronic night vision goggles.

Straw Man Purchase - A transaction where someone uses an intermediary to purchase something in order to conceal the identity of the true seller and or buyer. This is type of transaction is common when a type of merchandise is commercially available to some people but others are legally prohibited from buying the item. The prohibited buyer uses a "legal" intermediary to officially buy the merchandise who will then turn it over to the prohibited customer. BATF has been known to jail or fine gun dealers who knowingly engage in "straw man" sales to minors or convicted felons.

Survivalism - A term originally credited in the late sixties to Kurt Saxon and adopted by a number of writers to label a culture and philosophy of survival that emerged during the cold war and the social uncertainty of the late 1960ís and early 1970ís. The movement gained momentum in the 1980ís, with the high profile involvement of Vietnam Veterans giving birth to its own industry focused toward the interests and needs of survivalists. Survivalists have concerned themselves with preparing for and learning about survival during nuclear war, civil collapse and natural disasters. These preparations usually include the storage of large amounts of food, precious metals, weapons, and the accumulation of esoteric survival skills like wilderness survival, weapon handling, and alternative communications (Ham radio, Short-wave, the Internet). Modern survivalists frequently deal with preparations for living under or resisting oppressive government or conspiratorial plans to enslave or otherwise tyrannize the general population through the use of government power.

Survivalist - An individual who embraces and practices survivalism as a philosophy and lifestyle. Since survivalism is apolitical and non-religious in nature, but compatible with most worldviews, most survivalists are not exclusively survivalists, but rather combine the philosophy with a theology or political outlook on life. Examples of religious diversity in survivalist culture would be survivalist writers Kurt Saxon; a known Satanist, Bo Gritz; a devout Mormon, and John MacKalvaney; an evangelical Christian.

S.W.A.T. - Acronym for Special Weapons And Tactics. Originally coined by LA police chief Daryl Gates as Special Weapons Assault Team and changed for public relations reasons. The original stated intent was to give police departments (LA was the first) their own anti-terrorist capability, but S.W.A.T. teams are now most frequently used for drug raids and high risk arrests. A reference to elite para-military police units that are trained and equipped for high risk, high intensity close armed combat in urban environments. S.W.A.T. gear tends to be oriented toward indoor armed combat and is otherwise very similar to military equipment but is dark blue or black instead of military camouflage. Weapons tend to be compact and intended for short range engagements. S.W.A.T. teams use snipers for longer range engagements.

Nightscope - A slang term used to refer to all types of optical instruments that enhance the userís ability to see and or aim a weapon at night. See NOD, NVD, Starlight, Thermal imager.

NOD, NVD - Acronyms for Night Observation Device or Night Vision Device. An electronic optical instrument that enhances the userís ability to see at night. Some NVDs can be mounted on firearms and are used as weapon sights. Other NVDs and NODs can be used in conjunction with lasers or other illuminated sights in order to allow the user to aim a weapon in darkness. Infrared NODs are the most primitive of electronic light enhancing sights. NODs may be in the form of electronically enhanced telescopes, weapon sights, camera lenses, goggles, binoculars, or monoculars.

Post-ban, Pre-ban - Usually a reference to the time a firearm was made or sold in relation to legislation governing the legal status of certain parts or features.  Manufacturers usually delete certain features from a gun and even re-name the model when it becomes illegal to sell or manufacture.  Important bans and dates are listed in the chart below.  This is relevant when determining if a gun is in a certain legal configuration or not. 

1986 Full auto ban by Ronald Reagan - machine guns registered before this date  can be transferred among collectors, machine guns made or imported after that date are more heavily restricted.  Pre-ban guns trade at top dollar due to fewer restrictions, post ban models are restricted to government and dealers. 
1989 California, New York, and New Jersey lead the country with sweeping legislation against semi-auto assault weapons.  Companies change the guns and keep selling most of them in modified form.  Enforcement is minimal and selective.  New Jersey has most effective law. 

In the same year, George Bush begins to seriously hamper importation of similar guns through executive order, importers change names and configurations of models. 

Pre-ban European models from the late 1980's rise sharply in value and are considered the best ever to be available.  Post ban imports have uncomfortable thumbhole style stocks, no flash hider and no bayonet lug.  "California" models are changed mainly in name only by domestic manufacturers.
1994 President Bill Clinton signs Brady Law, restricting handgun sales and closes loopholes in Bush's effective ban on certain guns.   It also includes a sweeping ban on the manufacture of magazines that hold more than ten shots.  Considered the "big ban" by gun collectors.  Domestic US manufacturers must follow most of the same guidelines as importers.  Folding stocks become effectively illegal for newly made guns.  Large stockpiles of existing high capacity magazines are not affected by the law but prices go up.  
1999 California Governor Gray Davis passes sweeping legislation aimed at closing loopholes in earlier California law and recent federal ban by Bill Clinton.  All banned gun transfers are frozen at the stroke of midnight on January 2000.  Following New Jersey with a Magazine ban, California residents hoard existing magazines. 

Thermal Imager - An electronic optical device that converts heat to visible light so as to allow the user to "see" heat. The technology is more advanced than starlight and infrared in that it can also be used in the daytime and bad weather. It is also the most costly. Thermal imagers can be used to see through fog, smoke, and rain. Most thermal imagers are large and heavy. They can be damaged if exposed to too much heat and are best stored in refrigerated areas if outside temperatures are over 100f.  Higher technology units are not as vulnerable to damage from heat buildup.

TWS - Acronym for Thermal Weapon Sight. An electronic telescopic weapon sight that uses thermal imaging technology. Next generation infantry rifles have been designed to incorporate TWS technology. Unlike starlight or infrared, TWS actually "sees" heat.

Trigger Job - A reference to a modification of a firearmís trigger and related parts that is intended to enhance the smoothness and consistency of the firing stroke of the trigger. This tends to enhance accurate precision shooting of firearms since the shooterís aim is often disturbed slightly when the trigger is pulled. "A good trigger job" reduces the likelihood of the shooter disturbing his or her aim while pulling the trigger. Target guns tend to have trigger jobs that significantly lessen the amount of pressure that the shooter applies to the trigger in order to fire the gun.

Second Amendment, #2nd - A reference to the second amendment to the U.S. Constitution as part of the Bill of Rights (the first ten amendments of the U.S. Constitution). It reads ####. The meaning of which has been the subject of debate in considering American gun control laws. Most proponents of gun rights interpret consider it to mean that individual citizens have an absolute right to own and carry weapons, including firearms. Proponents of restrictive gun control laws and disarmament interpret it to mean that the right is collective and does not apply to individual citizens but rather only to the government collective rights.

Slam Fire - A reference to a type of malfunction in an automatic firearm where the gun is fired unintentionally when the bolt or slide closes on a live round. Slam fires happen occasionally with firearms that have "floating" firing pins that are not held back away from the primer by a small spring. Slam fires also can occur when internal parts have worn or been tampered with to the point that the hammer or striker engages the firing pin as the bolt or slide travels forward. Slam fires are often mistaken for full automatic fire since they are very similar. Slam fires often occur when a full auto conversion of a semi-automatic firearm was done improperly or a gunsmith was too ambitious in performing a "trigger job".

See Under Rings, See through base - References to scope mounts that allow the shooter a choice of using standard or telescopic sights on the same gun.  

Fluted Barrel, - A reference to a type of barrel that is similar to a bull barrel but has long grooves cut on the outside in order to reduce weight and enhance heat dispersion while gaining most of the performance benefits of a heavy barrel. They are usually found on premium quality sniper and target rifles.  

Weaver Grip, Weaver Stance - A reference to handgun techniques developed by Jack Weaver in the 1950s and 1960s and widely adopted by law enforcement and the military in the 1980s. The shooter uses a system of hand counter pressure and body alignment to steady a handgun during firing. The shooter uses both hands to hold the gun, the firing hand pushing slightly forward and the other hand placed over the firing hand pulling slightly back. The gun is aimed at an oblique angle to the body almost to the side opposite the "strong" hand, using the "strong" arm bone structure to serve as a from of "stock" for the gun.

Weaver Mount, Weaver rail - A reference to the industry standard interface between telescopic gun sight and gun. A Weaver style mount holds the sight in place by means of a dovetail and clamp mechanism that is usually tightened by means of screws on the scope rings. The rail is the dovetailed bar that is attached to the gun. The width, angle and height of the rail is supposed to be of the same general dimensions as the original "Weaver" base in order to ensure compatibility with the industry standard.  A modified version is known as the M1913 rail has been standardized by military contractors.

Quell grip, method, stance - A reference to Weaver techniques that have been modified for use by weak eye dominant shooters; i.e. left handed right eye dominant or right handed left eye dominant. The shooter also targets vital organs of the body different from those emphasized in most military and police training.

Zip Gun - A slang term referring to a crude homemade gun. Originally coined in the 1920s.