Airsoft, like any other sport, involves many scientific principles that go comparatively unnoticed. In the heat of battle, one rarely worries about something like the move of kinetic energy. While knowing airsoft physics will not realistically help you in a game, the principles are good to know. Knowledge of pellet ballistics, however, can help you with your game.
Pellets move very small amounts of kinetic energy mainly because of their size. The move of energy is basically the strength of impact. Airsoft and paintball energy transfers have been compared, and paintball transfers significantly more energy. Energy transfers are measured in joules, the SI derived unit of energy. A standard .20g BB traveling at 300ft/s transfers .8 joules, while a standard paintball traveling at the same speed transfers almost 12 joules. Energy move can truly be calculated using a mathematical formula; E = 1/2mv2, where E is joules, m is mass in kilograms, and v is velocity in meters per second. Since paintballs move more kinetic energy, they could be considered more damaging than airsoft pellets.
The weight of airsoft pellets considerably affects their speed and trajectory. The lighter a pellet is, the faster it will travel, but it will also be less accurate due to the fact it will be more prone to environmental factors like wind. Heavier pellets have straighter trajectories, so they are popular to lighter pellets, but in many situations heavier pellets cannot be used because the airsoft gun employing them is not strong enough to propel the pellets at a fast rate. consequently, players that wish to use pellets heavier than .25g usually need to upgrade their gun. Another assistance of heavy pellets is that they decelerate slowly, unlike light pellets, which start fast but quickly lose speed. Airsoft snipers usually use .30g pellets because of their high stability, but sniper weights can reach as high as .43g (although very expensive upgrades are required to use this grade of pellet). The heaviest pellet is .88g, which is never used in airsoft because it is incredibly slow, not to mention very dangerous, as it is usually made of steel.
Pellet velocity is determined chiefly by the tension of the spring being used to propel the pellet, or in the case of gas airsoft guns, the kind of gas being used. Energy move is relative to the speed of the pellet, and speed is also heavily affected by weight. For example, a .12g pellet using .800J (the shared energy rate of airsoft) of energy will initially travel 375fps. However, a .20g pellet employing the same amount of energy only travels about 280fps, and a .45g pellet will travel at about 200fps. For a .45g pellet to reach the velocity of a 375fps .12g pellet, it would need to utilize more than 2.50J of energy.
Bernoulli’s rule is the method by which pellets fly. It is, interestingly, also the rule by which airplanes reach lift. Bernoulli’s rule states that the velocities of fluids increase with a decline in pressure. In relation to airsoft, there is a fluid (air) above the pellet at a comparatively high velocity, which method the pressure above the airsoft pellet is lower than the pressure under it, as there is a smaller amount of air flowing under the pellet as there is above it. consequently, the pressure under the airsoft pellet pushes up and lifts the pellet, allowing it to fly for a long period of time. Hop-up systems in airsoft guns apply backspin to pellets, making air travel faster along the top of the pellet and creating a larger difference in pressure between the top and bottom.