Airsoft pellets

Airsoft pellets are spherical projectiles used in Airsoft gun models. Typically made of plastic, they usually range in size from 5.93 to 5.98 mm in diameter, though select models use 8 mm pellets. They are often called "BBs", referring to the ammunition of more dangerous BB guns (which are actually smaller and made of metal).

Special varieties of pellets

Although the majority of pellets bought and used are simple spherical projectiles made of plastic, these special varieties can be used to give a player an advantage:

Biodegradable

Biodegradable pellets are available, and are often required by outdoor fields where sweeping up is not an option. Conventional pellets are a pollutant of the environment - most ordinary pellets have a mineral or petroleum-based center coated non-biodegradable plastics, ensuring they will stay in the environment for several hundred years if not collected. Biodegradable pellets are made of various types of resin, often developed for the agricultural industry, and better makes are certified as compostable.

There is a mixture of degradable processes being used, such as soil microbes and photosensitive degradation. Biodegradable pellet development is now producing ammo with all the characteristics of the best of the conventional, with homogeneous resin construction.

Various EEC countries now only permit biodegradable pellet ammunition to be used, and many land agents are also insisting on their use on rented land. Airsoft worldwide is very late in coming to universal usage of biodegradable products which paintball has long achieved with its munitions.

Tracers

Glow-in-the-dark pellets, known colloquially as tracer pellets, can be used in conjunction with a device that "charges" the pellets by flashing them with a burst of visible light on leaving the barrel, so that they remain luminescent in flight for use during nocturnal games/operations. This tracer unit is usually hidden from view, often disguised as a suppressor (silencer), or is included inside the magazine. There are also biodegradable glow-in-the-dark pellets available.

Paintballs

Paint-filled pellets are also available, called markerballs, which are very similar to those used by paintball. Airsoft models equipped with the hop-up projectile stabilizing system are not able to use these, as the thin shells are liable to break in the barrel, soiling it with paint. These special pellets are also incompatible with Airsoft models using mechanized feed systems, such as high capacity magazines, for the same reason. With some companies, the use of paintballs voids the airsoft gun's warranty.

Markers

Recently, a new kind of pellet that leaves a small mark has emerged on the market. The pellets are coated with a powder that, when it strikes the target, a mark is left. Manufacturers include Verdict and Grudge Tactical.

Pellet weights

Pellet weight is an important factor when choosing pellets. The pellet's weight influences several aspects of pellet performance:

Velocity: Lighter pellets achieve higher velocities, but are more prone to influence from external factors like wind. Lighter pellets also decelerate (lose velocity) faster than heavier pellets. Due to the increased kinetic energy of a heavier pellet, it will hit harder than a lighter one.
Trajectory: The curvature of a projectile (trajectory) determines its range and lighter pellets result in much more curved trajectories. This can be negated in part by the use of a hop-up.

Hardware: Heavier pellets may require a more powerful airsoft gun and often necessitates upgraded springs and other gun parts.

A player's choice of pellet weight is governed by their gaming style, airsoft gun (internals), game location (in/outdoor), high/low range and ft/s regulations.

6 mm pellet weights and their usage

0.11 g - Manufactured by HFC, same use as .12 gram. Uncommon.
0.12 g - Used by all low grade weapons such as some spring pistols (which can use .20) and mini electrics. High velocity and low stability. Not to be used in high end AEGs such as Tokyo Marui and Classic Army. These pellets usually have a small air pocket in them.
0.135 g - Same uses s 0.12 g. Extremely Uncommon. MFI standard. Not to be used in high end guns.
0.15 g - Same uses as 0.12 g. Uncommon. Not to be used in high end Automatic Electric Guns (A.E.G.s) such as Tokyo Marui and Classic Army
0.16 g - Essentially the same as the 0.15 g pellets. Very uncommon.
0.20 g - A very popular weight for airsoft weapons. Standard for almost all velocity tests. AEGs are able to use these, however, most expierenced players will use heavier weights due to the increased accuracy and range.
0.22 g - Apparently no longer in production. Used to be available from KWC and Western Arms.
0.23 g - Heavier pellets for AEGs. Blends speed of 0.20 g with range and accuracy of 0.25 g. Made popular by Tsunami Airsoft
0.24 g - An oddity. Only known manufacturers are Airstrike (a subsidiary of Daisy) and Crosman
0.25 g - Heaviest weight for lower powered AEGs (314fps and under), blowback and spring guns. Tokyo Marui standard AEG, gas, and spring guns are set at the factory for 0.25 gram BB's, and they usually include a package of 200 of these with the gun.
0.26 g - Made by TSD in biodegradeable form.
0.27 g - Bioval BBBMAX,their tolerances allows them to be used by high fps sniper rifles and to some people more effective then higher weight BBs to a point. They are of the same grade, if not higher than the Maruzen SGM, while being significantly less expensive. These bb's are clear.
0.28 g - For upgraded AEGs or sniper rifles. Significantly cheaper than 0.30 g but yields similar performance
0.29 g - Maruzen Super Grandmaster BBs, designed for their Air Precision Shooting series of guns. One of the most precisely ground and accurate BBs available^{[verification needed]}, but cost more than other alternatives.
0.30 g - Standard weight for most sniper rifles. Western Arms pellets for their gas blowback pistol series. Uncommon.
0.32 g - Also standard for sniper rifles. Offer best balance of velocity and stability for most spring and gas sniper rifles.
0.36 g - Heavier pellets for sniper rifles. Very slow but have high stability.
0.40 g - Heavy pellets for airsoft sniper rifles. Mad Bull is a known producer. Even slower than 0.36g but even more stable and maintains kinetic energy better.
0.43 g - For the highest level of upgrades in spring and gas sniper rifles. Usually graphite coated.
0.88 g - Possibly the heaviest type of BB available. Usually made of steel and comes with a polished finish. Rarely used and often hard to find. This is a BB not used in airsoft, it is usually used for actual BB guns and/or target practice.

8 mm pellet weights

0.27 g - Low weight
0.34 g (Normal)- Standard weight
0.35 g (Biodegradable)- Standard weight
0.4 g
0.45 g - Heaviest weight

Pellet ballistics

Pellet speed, energy and weight

The pellet speed of automatic electric guns is determined in large part by the tension of their main spring and so there tends to be a stratification of values. The most common airsoft speed limits are between 300 and 400 ft/s (91 and 122 m/s) for AEGs and 400 to-^{[convert: unknown unit]} for single shot guns (sniper rifles). Below are some common speeds of airsoft pellets.

As for comparison purposes, 3.00 g is the typical weight for a paintball pellet. At this weight a pellet flying at 100 metres per second (330 ft/s) results in 15 J. Such energy levels and weight are not used on Airsoft, but comparing them with airsoft energy levels is useful to show the presence of different collisions in these sports. Higher energy but different collisions read Elastic collisions (airsoft) and Inelastic collisions (paintball) topics for further information.
Red line in speed vs energy image is the usual Crony (chronograph) weight for 6 mm (0.20 g).

Dangers to humans

Airsoft pellets typically leave small wheals (welts) on human targets. While mildly painful, pellets are not especially damaging to the skin. Eye protection is universally required to prevent damage to eyes. It is also often recommended that full face masks and body protection be used during airsoft matches to protect the players' teeth and ears.

Although there have been no documented cases in airsoft, there is a possible hazard when dealing with graphite-coated pellets. In the early days of paintball some players would coat their rounds with graphite so that they would feed into the gun better. Players started to find that if any rounds broke the skin, the wound would not properly heal, leaving a scar. Players and field owners should be aware that this problem may exist in the realm of airsoft as well.

The following excerpts are from the United Kingdom Parliament's "Principles of firearms control", Home Affairs Select Committee Second Report, 6 April 2000, expound on the level of danger involved with low-energy projectiles:

"25. The Firearms Act 1968 defines a firearm "a lethal barreled weapon of any description from which any shot, bullet or other :missile can be discharged".[51] In this context, a "lethal weapon" means a weapon capable of firing a projectile with sufficient :force to inflict more than a trivial injury, i.e. with a force sufficient to puncture the skin.[52] The force with which a firearm :is able to deliver a projectile is normally expressed in terms of the kinetic energy it generates at its muzzle—the "muzzle energy". :This energy is normally expressed in units of foot-pounds (ft·lbs) or joules (J).[53]
"26. The Home Office and the Forensic Science Service considers that the lowest level of muzzle energy capable of inflicting a penetrating wound is one foot pound force (1.35 J): below these power levels, weapons are "incapable of penetrating even vulnerable parts of the body, such as the eye".[54] However, more recent analysis by the Forensic Science Agency for Northern Ireland has indicated that a more reasonable assessment of the minimum muzzle energy required to inflict a penetrating wound lies between 2.2 and 3.0 ft·lbf (3 to 4 J).[55] We will deal more fully with this discrepancy at paragraphs 123 to 130 below."
"123. The power level at and above which an air weapon is considered a firearm in law is presently set at 1 ft·lbf. However, we note above that the Forensic Science Agency of Northern Ireland has more recently assessed the power level at which a barreled weapon is capable of inflicting a lethal wound as between 2.2 and 3 ft·lbf, and the Secretary of State for Northern Ireland has proposed that the law relating to firearms in Northern Ireland be amended to take this into account.[201]"

On another document also regarding firearms, "The Eleventh Annual Report of the Firearms Consultative Committee", the penetration levels lies between 2 and 3 J based on a research for US Army and DiMaio's work in "Minimal Velocities Necessary for Perforation of Skin by Air Pellets and Bullets, Journal of Forensic Sciences".

Date	Reference	Energy level	Observations
April 2000	Principles of firearms control [paragraph 26],Home Office and the Forensic Science Service;	1,35J	penetrating wound (later changed by paragraph 123, see below)
April 2000	Principles of firearms control [paragraph 123], Forensic Science Agency for Northern Ireland;	3,00J~4,00J	penetrating[26]/lethal[123] wound
March 2002	The Eleventh Annual Report of the Firearms Consultative Committee DiMaio's work in Minimal Velocities Necessary for Perforation of Skin by Air Pellets and Bullets,Journal of Forensic Sciences;	2,00J~3,00J	penetration level