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- 3 Position 3-pos | See Three Position Selector
3 Round Burst | See Three Round Burst
4 Position 4-pos | See Four Position Selector
- ACOG
Advanced Combat Optical Gunsight
A magnified optic made by Trijicon, originally for the M16 and M4 platforms but now available for an array of infantry small arms.
See Also: VCOG | MCOG | External Links: | Wiki | Free Dictionary Acronyms
ACR
Advanced Combat Rifle
The Advanced Combat Rifle Program was a research and evaluation done by the US Army and key arms manufacturers in the 1980's.
See Also: AICW | AIWS | SPIW | External Links: | Wiki | Global Security | Military Wikia: ACR
ACRT Advanced Combat Rifle Technology | See ACR
ACWS
Advanced Crew Served Weapon
A US military program that led to some heavy machine guns and belt-fed grenade launchers. Sometimes listed in older literature as Advanced Combat Support Weapon.
See Also: AGS | HMG | SAW | External Links: | Wiki
Adaptive Combat Rifle
ACR
A rifle designed by Magpul to compete with the ilk of the SCAR program. Dubbed the Masada and later licensed to Bushmaster.

External Links: | Wiki | Bushmaster ACR | Remington Defense ACR | Magpul Masada Announcement, Licensed to Bushmaster
AK
Avtomat Kalashnikova
Automatic Kalashnikov. The Kalashnikov series of rifles consisting most famously of the AK-47, AKM, AK-74, and AK-101 series or rifles. Often to include any design based on the AK-47 and AKM.
See Also: AK-47 | AKM | Kalashnikov | External Links: | Wiki
AK-47
AK47
Автомат Калашникова образца 1947 года or "Kalashnikov automatic rifle model 1947". The first production AK, differing primarily from later designs in having a milled receiver. Chambered in the M43 cartridge. Replaced by the AKM.
See Also: AKM | Avtomat Kalashnikova | M43 | External Links: Dictionary | Wiki
AK-74
AK74
Автомат Калашникова образца 1974 года or "Kalashnikov automatic rifle model 1974". Similar to the AKM but chambered in the M74 cartridge. Adopted by many Warsaw Pact countries, in 1974 or later.
See Also: AKM | Kalashnikov | M74 | External Links: | Wiki
AKM
Автомат Калашникова Модернизированный (Avtomat Kalashnikova Modernizirovanniy, Kalashnikov modernized automatic rifle). This stamped sheet metal receiver version of the AK replaced the AK-47 officially in the USSR in 1959.
See Also: AK-47 | AK-74 | AK | External Links: | Wiki
AKS
Автомат Калашникова Складывающимсая (Avtomat Kalashnikova Skladyvayushchimsaya, Automatic Kalashnikov folding rifle).
See Also: AK-47 | AK | AKM | External Links: | Wiki
AR
ArmaLite Rife
The leading model letters on ArmaLite brand weapons, such as AR-10, AR-15, and AR-18 represented ArmaLite Rifle and not Assault Rifle as has been assumed.
External Links: | Wiki
ARA Advanced Research Agency | See DARPA
ARDEC
Armament Research Development and Engineering Command
Located at the Picatinny Arsenal in New Jersey, United States Army Armament Research, Development and Engineering Center is the primary arms research arm of the US Military.
External Links: | Wiki
Assault Rifle
An assault rifle has a very specific meaning. It is a select fire rifle firing an intermediate cartridge and utilizing a detectable magazine.
An intermediate cartridge fits between a high-power and sub-caliber cartridge. Therefore, a high-powered assault rifle would be a misnomer.
All assault rifles are regulated under the USA National Firearms Act of 1934 as machine guns.
See Also: Selective Fire | External Links: | Wiki
Assault Weapons Ban
1994 AWB
The now defunct Federal Assault Weapons Ban passed in September 13 of 1994, with a ten year sunset expiration, if not renewed (expiring on September 13, 2004). This law impacted only firearm manufactured during the dates of the AWB.
The law banned certain semi-automatic firearms based primarily on cosmetic features but also on magazine capacity. These were referred to as assault weapons, not to be confused with the more defined and already highly regulated assault rifles.
See Also: Assault Rifle | External Links: | Wiki
Automatisch
Automatic [Dutch/German]
See Also: Automatische | External Links: Dictionary
Automatische
Automatic [Dutch/German]
See Also: Automatisch | External Links: Dictionary
- Burst Mode
Burst Fire
An automatic firing mode consisting of a short burst. Most often a burst is three-rounds per trigger pull, but other configurations such as two and four exist. The burst is almost always controlled by a cam that trips the trigger mechanism for each shot fired in the burst.
See Also: Selective Fire | Full Auto | Three Round Burst | External Links: Dictionary | Etymology | Wiki
- Cupronickel
Copper-nickel
Often visually mistaken for tin or just nickle, it is actually primarily made from copper. This is an alloy used in coins and ammunition jacketing. The blend comes out a white (silver) metal color and often has enough iron, for strengthening, to be magnetic. Manganese is also present.
External Links: | Wiki
- Four Position Selector
Four Way Selector
A select fire selector with positions for safe, semi-automatic, burst mode, and full auto.

See Also: Burst Mode | Three Round Burst | Full Auto | External Links: | Robrobinette.com M16 4-Way Selector Install
Full Auto
Fully Automatic
A select-fire firearm which continues firing, by cycling ammunition itself, until the trigger is depressed.
See Also: Selective Fire | External Links: Dictionary | Wiki
- Karabiner
Carbine [German]
See Also: Carbine | External Links: Dictionary
- National Firearms Agreement
1996 NFA (AU)
In the USA this often refereed to simply as the '1996 Australian gun ban' but is more correctly a law that strictly places firearms into categories. Each individual is required to meet specific approvals and licensing to own a firearm in that category.
See Also: Assault Weapons Ban | External Links: | Wiki
- Rate of Fire
Firing Rate
The frequency at which a firearm fires projectiles. This site lists the rate of fire (ROF) as rounds per minute (RPM).
See Also: Selective Fire | Full Auto | Burst Mode | External Links: Dictionary | Wiki
- Selective Fire
aka Select Fire
A selective fire weapon has a selector capable of choosing firing modes between semi-automatic and at least one automatic (full or burst) mode.
See Also: Full Auto | Burst Mode | Semi-Auto | External Links: | Wiki
SPIW
Special Purpose Individual Weapon
A US Army program to develop a flechette-based weapon and other related technologies. Directly related to the Future Rifle Program and the Advanced Combat Rifle program.
See Also: ACR | AICW | Future Rifle Program | External Links: | Wiki
- Three Position Selector
Three Way Selector
A three position selector with positions for safe, semi-automatic, and a select fire mode. Most common is safe, semi, and full auto.

However, a three position selector of safe, semi, and burst mode has become more common.

There also exists selectors with positions for safe, burst, and full auto (not shown).
See Also: Burst Mode | Selective Fire | Three Round Burst | External Links: | Wiki
Three Round Burst
A three position select-fire firearm which continues firing, by cycling ammunition itself, until three rounds have fired or when the trigger is depressed. Two and four round burst firearms also exist.
See Also: Selective Fire | Three Position Selector | Four Position Selector | External Links: | Wiki
- Zytel
Nylon Resin
Zytel is a DuPont brand name for proprietary nylon (a thermoplastic polyamide), often with varying amounts of fiberglass. These thermoplastics are impact resistant, high strength, and are made stiffer with the inclusion of the fiberglass.
External Links: | Wiki | Chemical Tradename Dictionary | Whittington's Dictionary of Plastics | DuPont.com Zytel Nylon Resin