Or something like that! Basically, that the whizz-bangs don´t (or won`t!) land anywhere outside the training area. This used to be a hot subject for the artillery in Hong-Kong. At the far end of the artillery range was Macao - and, if the amount of cordite in the shell was wrongly calculated, it used to happen that the shell didn`t land in the sea, but in someone´s back-vard! Rather embarrassing - and potentially expensive if someone was sunbathing.