I have fired loads of frangibles and they do a fine job of disintegrating on more than metal or stone.
Wood, fibreglass, windshield glass, sometimes drywall.
Your mileage may have varied.
Your claimed results are far different than the companies that manufacture or load frangible bulleted ammunition and the federal government law enforcement agencies that train with it and the military that uses it. It seems most probably that you are fabricating a B.S. story to cover ignorance.