Airsoft pellets

Low-quality 6 mm 0.12 g plastic airsoft pellets

Airsoft pellets are spherical projectiles used in airsoft gun models. Typically made of plastic,[1] they usually measure around 6 mm[2] in diameter, though select models use 8 mm and weigh 0.12–0.48 g, with the most popular weights being 0.12g, 0.20 g, and 0.25g. While airsofters almost always call them BBs (bearing balls), they are not the same as the 4.5 mm projectiles that BB guns fire.

Variants

Although the majority of pellets bought and used are simple spherical projectiles made of plastic, some of the following 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 pollute the environment, as most non-biodegradable pellets have a mineral- or petroleum-based center, coated in non-biodegradable plastics, thus 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 pellets are currently being produced with all the characteristics of the best of the conventional, with homogeneous resin construction.

Most high-quality pellets are available in a non-biodegradable version, as well as a biodegradable version that costs slightly more. Both bio. and non-bio. pellets are popular and widely available.

Tracers

Glow-in-the-dark pellets, known as tracer pellets, can be used in conjunction with a device that "charges" the pellets by flashing them with a burst of light before 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 or hop-up unit. There are also biodegradable glow-in-the-dark pellets available.

Non-traceable pellets

This type of pellet is dark-colored so that the opponent has a tougher time spotting the pellets' origin. The most common color is white, which makes it easy for the opposition to spot the shooter by following the trail of pellets. Two major problems of this variant of pellet are that there are few high-quality pellets in this color and the shooter has a difficult time seeing his own trail of shots.

Paint-spherical projectiles

Paint-filled pellets are also available, called paintballs, which are very similar to those used in 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; paint may get into the mechanical workings of the airsoft gun and damage parts beyond simple maintenance. These issues may be fixed by removing the hop-up unit, which can void the warranty, and also switching to a low or mid-capacity magazine with no mechanized feed.

Markers

A specialized pellet, coated in a powder that leaves a small mark when it strikes a surface. Powder deposits from these pellets are left in any part of the airsoft gun or storage unit that the pellet comes in contact with, and build-up over time, without cleaning, can cause malfunctions or damage to moving parts.

Silica or bio-inert

Made from 100% silica, the material in these BBs is very evenly distributed, improving flight characteristics. Some accounts indicate that these BBs are capable of breaking glass and industry-standard protective eyewear. Due to safety concerns and reports of injuries caused by this BB type, it is commonly prohibited in professional airsoft facilities.

Metallic

Metal pellets are also marketed for use in airsoft guns. These pellets are heavier and harder than conventional polymer airsoft pellets, and the impact from a metal pellet can injure players. Safety concerns make metallic pellets suitable only for target shooting. The added weight reduces the effect of crosswind on the pellet, imparting more accuracy when fired at longer ranges in outdoor environments where wind would significantly alter the trajectory of traditional pellets. Many airsoft locations where players can pay to play against others prohibit the use of metallic pellets due to the fact they are more likely to penetrate skin. Metallic pellets are mostly used in a standard pump-action or carbon dioxide-powered BB gun.

Ceramic

Created from lab grown crystal lattice structures, these BBs are individually machined to precise specifications that ensure uniform weight, dimensions, and surface shape. This precision and uniformity provides ideal ballistic performance and consistent flight patterns. The manufacturing process and materials are much more costly than molded polymer pellets - as a result, ceramic pellets are considerably more expensive than standard airsoft pellets. The material is hard enough to defeat standard eye protection at high velocities, and these pellets are not suitable for close-quarters play.

Pellet mass

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

Velocity:

Energy:

Trajectory:

Hardware:

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

Also, quality of the individual BBs may influence choice of price-range or manufacturer. Low-cost BBs are often considered to have such negative characteristics as residual plastic from the moulding process (flash); lower impact resistance and some deviation from perfect spherical shape. Cheaper BBs are known to shatter when fired, which can cause irreparable damage to the internals of the gun. Higher cost BBs generally have a smoother finish, are more impact resistant and are perfectly spherical.

6 mm Airsoft pellet mass and their usage

8 mm Airsoft pellet masses

8 mm pellets are most commonly used in gas-powered airsoft shotguns with high velocities.

Pellet muzzle velocity and energy

The pellet speed of automatic electric guns is determined in large part by the tension of the main spring of the gun. Airsoft muzzle (at gun's exit) speed limits are between 90 and 120 m/s (300 and 390 ft/s) for AEGs and 120 to 170 m/s (390–560 ft/s) for single shot guns (sniper rifles).

Velocity vs. energy chart for 6 mm Airsoft pellets.

For comparison purposes, 3.00g is the typical mass of a paintball pellet and 0.2g is the standard for an airsoft pellet. At 3g mass, a pellet flying at 100 metres per second (330 ft/s) results in 15J of kinetic energy, while a 0.2g results in 1J. It is important to distinguish that, on airsoft, the impact energy is very close to the kinetic energy of the pellet because the collision is almost elastic. On the other hand, in paintball, the pellet disintegrates on the collision, leading to an inelastic collision and thus the impact energy is smaller than the kinectic energy of the pellet. Nevertheless, the typical impact energies of the airsoft pellet tend to be much smaller than of the paintball.

Pellet ballistics

While the pellet's velocity leaving the airsoft gun is important for safety proposes, during flight, it loses velocity due to drag. The typical deceleration of a pellet of mass "m" and diameter "D" is given by the quadratic drag:

impact energy dependence on distance of impact for a typical airsoft pellet
A_\text{drag} = \frac{1}{2m}\rho_\text{air} v^2 \cdot 0.47 \cdot \pi \left(\frac{D}{2}\right)^2

where v is the instantaneous velocity of the pellet. For typical values of the pellet (m = 0.2 g, v = 120 m/s, D = 6 mm), the drag can be very high (576\ \mathrm{m}/\mathrm{s}^2) which means that the velocity decreases quite fast. In particular, for typical values and neglecting wind effects and hop-up techniques, a straight shot from a height of 1.8m has a range of 34m. On ground hit, the impact energy of the pellet is 0.1 J. However, the same shot at close quarters (e.g. 5m distance) has an impact energy of 1J (see figure).

Dangers to humans

See also: Airsoft Safety

Airsoft pellets traveling with sufficient velocity will leave small lesions when striking exposed skin. While painful, pellets are not typically damaging to the skin. Airsoft pellets can cause serious damage to more vulnerable parts of the body, such as the eyes and ears. Full face masks are recommended during airsoft matches to protect players' teeth and ears, and eye protection is universally required.

The critical velocity required for skin penetration can be calculated using the formula:

v_\text{cr} = 162.1 e^{-0.38 \sqrt{m}}

where m is the mass of a spherical bullet, in grams. Penetration is defined here as entering the skin to a depth of more than half of the spherical pellet's diameter.

Accordingly, a typical 0.2g airsoft pellet will penetrate the skin at 136.7 metres per second (448 ft/s).

The following excerpts 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, 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

References

  1. ↑ Sira, Habibu (19 June 2013). "Airsoft guns are available online". The Star. Retrieved 29 June 2013.
  2. ↑ "What is an electric rifle? AEG Airsoft guns explained". Airsoft Atlanta. Retrieved 27 June 2013.
  3. ↑ "Measuring the Velocity and Kinetic Energy of Airsoft BBs using a Ballistic Pendulum", Branden Fletcher, Jason Cross, John Cavassa, and Riley Compton,

See also

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