However, the school cannon that blew up was made in the school's metal shop in the 1980's, therefore being at least 17 years old up to 26, and then therefore possibly fired thousands of times, while the natural acts of corrosion and accumulative use took its toll. Nothing against Mythbusters, but they didn't fire the thing for years, either. Apples and oranges.
That is true, and the picture I saw of the cannon showed it to have a thin barrel.