I was surprised at hearing the "no projectile whatsoever" rule. Is that a base rule?
It's my understanding that airsoft and model guns (guns that operate exactly like real guns but cannot fire) were born in Japan. Consequently, all airsoft guns must shoot less than a joule of force (.98 joules to be exact).
Copy-n-paste nerdiness (with some cuts) to follow: To calculate the power of an airgun you need to use a chronograph to measure the speed of the pellet (in feet per second) when fired, and you need to know the weight of the pellet in grains. Once you have that information you perform the following calculation: - speed (ft/sec) X speed (ft/sec) X weight (grains)
this gives you the result in foot pounds force (ft-lb).
The legal maximum for an unlicensed air rifle is 12 ft-lb which from changing round the above formula, gives the approximate values as follows:-
A .22 pellet weighing 14.4 grains, maximum permissible speed is 612 ft/sec
A .177 pellet weighing 7.9 grains, maximum permissible speed is 826 ft/sec
The corresponding figures for a pistol are 433 ft/sec for a .22 and 584 ft/sec for a .177
The pellet weights used in the above calculation are typical weights for the sizes of pellet but you must always check the actual weight of your pellet before performing your own calculations. (
Original Source)
The only "problem" with the above is that airsoft BBs come in so many varieties: .12g, .20g, and .25g. All are 6mm but there many differing weights in grams. Regardless, plenty of choices to make you legal with an airsoft gun that fires.
