Due to the low muzzle energy (less than even for high-power models) and poor sectional density, the pain an airsoft pellet causes on skin impact is about the same as getting pinched. As a reference value, a standard 0.20 gram 6 mm pellet, which is the most common size and weight, traveling at has of kinetic energy. Calculating the Joules and energy generated by airsoft guns is important because of phenomenon like "joule creep" where the FPS remains the same while the energy of the airsoft BB leaving the airsoft gun barrel increases.