Originally Posted by Belaslav
EDIT: Someone pointed out a mistake in my logic, I really didn't need a "biconditional" only "IF". Sorry, it was morning and I wasn't thinking clearly.
Ie. Mathematically you need to have P AND Q => Illegal this means 500 FPS AND 5.7J of impact force is illegal. Taking the opposite of that (DeMorgan's Law) ~P OR ~Q => Legal. This means if it shoots 500 FPS on a .20g BB it won't have nearly the amount of impact force to be a controlled firearm). (It still might need to be XOR though).
A whiffle ball going at 500 FPS (even though I don't think that's physically possible) isn't the same as a pellet gun going at 500 FPS because the impact force and energy transferred is too low on the whiffle ball.
Really what we in airsoft should be saying is that field limits are X Joules but then people would have to do some math-fu to figure out what they're shooting at. It's much easier to lock one variable (weight of BB) at chrono and then figure out the speed after that.
PS: I'm almost sure that there's something else wrong in my mathematical logic here but I just can't see it but I hope you get the idea.