OK. I don't normally go for subtleties but here is a distinction.
Joe, the guys' concerns are valid, but I've lived on isolated properties and have firearms so maybe there's another side to this.
Sometimes we say, or describe, things in a way that is open to mis-interpretation and can alarm others. (I do it with my lass all the time).
Now, the way I see it, there are two takes on what you said you did -
1. Something triggered you and you went out of control and shot up the scenery with half a box of rounds before reality re-asserted itself. As Angle and others remarked, could've gone horribly wrong.
Or.....
2. Something on TV pissed you off to the extent that you got into a foul mood (I know how quickly that can happen) and you thought 'bollocks to it' and went outside quite deliberately with the intent of putting thirty rounds into the dirt, confident that you could without any consequences (be different once you've got horses, though). Not much chance of anyone, let alone followers of Allah, turning up while you were doing pistol practice....
Case 1 is not good, Case 2 is no different to shooting the f=#k out of a target, but less rewarding..........
Thing is, mate, you've got to be honest with yourself. Which was it?
One final thought. Put those targets up. Safest direction, whatever face you want on them, and patch them up between sessions. (see if there's constructive improvement, don't just make the gun go bang).