I see a personal grudge, or a serious dick *somewhere* in this mess.
I dunno about Scotland so much, however the AirSoft devices my eldest have are like hell made out of plastic, nor do they use springs as firing mechanisms. The name makes it pretty clear what they use to fire those balls with.
And he *has* mucked with it and gotten the pistol muzzle velocity up over 328fps. Mind you after it popped two sandbags and I made him clean that up he choked it back. And despite more than a few months of practice I'm still 45% more accurate than him on a stationary target. (75 ft range)
Still and all, the groups over here are pretty damned harsh on modders that overramp and to get in any playfield they get to test your device before you go out.
This cop and the Sheriff/judge both need a swat, it is after all a (slightly weird) "sport", not a "terrorist" organization.