Airsoft is full of acronyms and terms that can be very difficult for a new player to understand. We’ve devised this list to help you find a descriptions for these difficult terms. (ctrl + f, to search)
If you’re new and can’t find a term on this list, drop us an email at We’ll answer your question and add it to the list.

Active Braking – The act of reversing the current flowing to an AEGs motor in order to stop it from over spinning (see over-spin) this is usually a feature in mosfets and is often shortened to a AB.

AEG – (Automatic Electric Gun) is an airsoft gun that fires BBs through the use of batteries, motors and gears. An AEG is the primary kind of airsoft rifle that you will see at a skirmish.

AOE – (Angle of Engagement) refers to the angle of which the first tooth of the sector gear engages the first tooth on the piston. If this angle is not set tuned correctly, it can put unnecessary strain on the piston and cause it to fail.

ARL – (Anti Reversal Latch) The Anti Reversal Latch is a spring loaded latch on the Bevel Gear that stops the gears and motor from travelling in the opposite direction when stopped under load (see over-spin).

BASR – (Bolt Action Sniper Rifle) Refers to the kind of sniper rifle that requires actuation of the bolt to chamber a round after every shot.

BB – (Ball Bearing) the ammunition that we fire in airsoft. Primarily, we use 6mm BBs (although 8mm is occasionally used) and they come in various weights ranging from 0.20g to 0.45g+.

BBU – (Blow Back Unit) The Blow Black Unit is part of a GBB and GBBR. It holds the Piston, Loading Nozzle, Rocket Valve or NPAS. It receives the gas that has been shut off from the barrel by the rocket valve and begins the process of moving the bolt backwards. 

Blow-Back – Refers to the act of a airsoft gun’s “bolt” being cycled whilst firing.

Bucking – The Bucking is the part of the hop-up that directly interaces with the BB travelling down the barrel. It also provides an air seal to ensure all air from the gearbox travels down the barrel.

Deans – Deans is a kind of battery connector. It is widely considered to be the best as it offers the best compromise between size and circuit resistance.

DMR – (Designated Marksman Rifle) DMR usually refers to a accurate semi-automatic long range rifle.

EBB – (Electric Blow Back) This is blow back created by an electric gun, usually a weight attached to the AEG’s piston.

EyePro – (Eye Protection) EyePro refers to eye protection in airsoft. It’s important to get high quality eye protection in airsoft. 

EndEx – (End Exercise) Often shouted to signify the end of an airsoft skirmish to signify its end.

Flat-Hop – A kind of hop modification that is less difficult to install than R-hop. It involves removing the mounds on your hop-bucking and using a larger nub for a more consistent hop.

FPS – (Feet per Second) refers to the speed at which a BB leaves an airsoft gun’s barrel. 

GBB – (Gas Blow-Back) is a general term for an airsoft gun that uses gas to fire the BB and simulate recoil by actuating its bolt (often used to refer to pistols with a moving slide). 

GBBR – (Gas Blow-Back Rifle) is a rifle that is powered by gas and uses that gas to move its bolt, simulating recoil.

High Cap – (High Capacity) High cap refers to the most common kind of airsoft magazine. They hold upwards of 350 rounds and are standard issue with most airsoft rifles. Many experiences airsofters move away from these magazines, due to the fact that they rattle when moved. AKA: Hi-Cap.

Hop-Up – A Hop-Up is part of more modern airsoft guns. The hop-up imparts an adjustable amount of back spin on the BB. This back spin gives the BB lift (The Magnus Effect), thus increasing its range.

Hop – A term generally used to describe the act of applying hop-up.

HPA – (High Pressure Air) HPA is a type of gas used in airsoft. It’s often used in GBBR or PolarStar type airsoft guns. It usually requires a paintball like air tank and a remote air line.

LiPo – (Lithium Polymer) is a kind of battery used in airsoft. They’re less common than other types of battery as they’re considered more volatile and harder to charge. Whilst it is true they do require special care, they also offer higher discharge rates and smaller sizes.

Low Cap – (Low Capacity) Low Cap refers to a kind of magazine and are sometimes called ‘real cap’ for their realistic ammo capacity. A Low Cap STANAG holds 30 rounds.

Mid Cap – (Mid Capacity) Mid Cap refers to a kind of magazine. They use a similar internal mechanism to ‘low cap’ magazines but hold a higher capacity (roughly 100-200). These are popular as they do not rattle when moved, yet hold a relatively high capacity.

Mosfet – A mosfet is a small electrical component that can be fitted to an airsoft AEG. Its primary function is to protect your trigger contacts from electrical arcing; It does do by directing the current directly from the battery to the motor when the trigger is pulled. Due to their ability to control your AEGs trigger, they often have secondary function. Such as, programmable fire mode and LiPo protection. 

NBB – (Non Blow-Back) refers to a airsoft gun that does not have a blow back function, this is quite often used to describe airsoft pistols where the slide does not move. 

NiCd – (Nickel–Cadmium) A kind of battery often used in airsoft.

NiMh – (Nickel–metal-hydride) A kind of battery often used in airsoft.

NPAS – (Negative Pressure Air System) An NPAS is an adjustable small piece inside a GBBR (replacing the rocket valve) that adjusts the amount of time that gas is forced down the barrel, thus adjusting its FPS.

Nub – The nub is the part of the hop-up that applies pressure onto the bucking.

Over-Spin – Where the residual energy left in an AEG motor continues to turn the gears and piston for a short time after the trigger is no longer pulled; This results in the piston and spring being left in a compressed state.

P* – (PolarStar) PolarStar was one of the first manufacturers in airsoft to develop a HPA system that directly replaces an AEGs gearbox. This converts it from battery power to HPA powered.

R-Hop – A kind of hop-up modification developed by HunterSeeker5. It applies hop-up gently, over a longer time improving consistency, accuracy and range.

RoF – (Rate of Fire) refers to the number of BBs an airsoft rifle fires over a set period of time. This is usually measured in rounds per second (rps) but can be measured in rounds per minute (rpm).

RPS – (Rounds per Second) RPS is a measure of an airsoft gun’s rate of fire.

RPM – (Rounds per Minute) RPM is a measure of an airsoft gun’s rate of fire.

Shim – A small ring of metal that removes space between the bushing / bearing and the gears stopping them from moving along the axle axis. This ensures that the gears are gears always engaged optimally, this improves durability and performance.

STANAG – (Standardised Nato Agreement) This terms is widely used to refer to the standardised magazine used across many weapons platforms, such as AR-15/M16.

Tamiya – This is the most common battery connector in airsoft. It comes in both Large and Small variants. However, it is often swapped out for Deans connectors as they offer less electrical resistances in a similar size.

V1 – This refers to the version of an AEGs gearbox. This gearbox was designed by Tokyo Marui for their FAMAS rifles and is one of the first AEG gearboxes designed. The motor is housed directly inside the AEG gearbox case.

V2 – This refers to the version of an AEGs gearbox. This gearbox design is the most common AEG gearbox design. It’s used in M16 type rifles as well as G3 and MP5 style AEGs. The motor is held in place by the rifle’s pistol grip.

V2.5 – (V2 Extended) This refers to the version of an AEGs gearbox. This gearbox design is based on the V2 gearbox design but with an extended cylinder and piston assembly. This is to provide greater air volume to longer barrel rifles.

V3 – This refers to the version of an AEGs gearbox. This version is widely used in AK, G36 UMP and AUG types of rifle and is the second most commonly used design. Its motor is held in a separate motor cage that is bolted to the gearbox shell.

V4 – This refers to the version of an AEGs gearbox. The V4 gearbox is a rare gearbox type that is only used in PSG-1 rifles. It provides a unique, pre-cocking feature that gives instant trigger response. 

V5 – This refers to the version of an AEGs gearbox. The V5 gearbox is a rare type of gearbox that is only used in UZI style rifles.

V6 – This refers to the version of an AEGs gearbox. This type of gearbox is used in Thompson and P90 style AEGs. 

V7 – This refers to the version of an AEGs gearbox. This type of gearbox is used primarily m14 style rifles.

V8 – This refers to the version of an AEGs gearbox. This type of gearbox is used for type-89 style rifles and is similar in to V2 gearboxes but features a gear operated burst function.

We are always looking to add to this list. Please drop us an email at if you have anything to add or amend!