Quote Originally Posted by harvey_s View Post
Surely you've covered the answer in the section you've quoted?.... In that the kinetic energy is a calculation of what is discharged from the muzzle and if there is more than one missile discharged then it's the TOTAL energy of the discharge.
That's your interpretation Harvey, surely? The law says a missile, singular, like a bullet.

Dust shot individually are pretty harmless at range. Obviously if you fire a single, solid mass you may put it over the limit and render it illegal - just like owning a functioning air cane is legal until you actually use it.

Don't forget, the law tolerates all kinds of devices that deliver missiles of high KE but generally low accuracy, like a catapult, slingshot, or even a throwing hammer! The reason guns are singled out for restrictions is that they can potentially deliver destructive missiles with accuracy at range.