I lived in Durrington, in the early 80s, so our playground was ‘tankie’, officially known as Charlie crossing. There was a hill that we would sometimes sit on watching until training troops pulled outIn the old army buildings near everleigh by any chance? I found a dummy anti tank bar mine thing near there and was cycling home with it when I got stopped by the mps.
We found many things, mostly collecting spent blanks and link. Taking them to school for metal work class cutting the ends off the blanks and making belts to sell to the rest of the school. The general currency being Penguin bars.
Live blanks would be fired off by doing something dodgy with an air pistol, sometimes the full blank, sometimes cutting open first for the contents and firing off the percussion cap via airpistol