The ammo was a APFSDS round at 170g traveling slightly over the speed of sound as I can remember.
The target was a 1" steel plate wich now turns out to be something awfully hard like armour or tool steel.
Well, my brother bought that house and is now doing renovation. As he was taking the panels of the walls and tearing out the insulation he found what I spent so many hours looking for.
It had penetrated the wall completely sideways and crushed anything in its way before lodging itself in the drywall at the very end. Pretty lucky it didn't penetrate 100% eh?
Thought it might be interesting to see for those who remember, and it goes to show that you should not mess around with spudguns. I learn't my lesson that day.


Edit: This is a very similar projectile before firing.
