Jim I would "Bet the Farm" that gun you had was fired with an obstruction if a full investigation had been carried out to determine cause

2-piper:
Unfortunately we'll never know what caused it to let go as I didn't think it was of any real importance at the time which was over 20 years ago. I however can tell you this: The undamaged right barrel was in pristine condition and didn't even exhibit any minor pitting. I can only relate what the owner told me. He had personally cleaned the gun before use and it was his practice to always look down the barrels during assenbly to make sure they were clear. As I stated above; He told me the barrel burst on the first shot the next time is was used. I did ask about 20 gauge shells and he stated he didn't even own a 20 gauge.
Jim

The 2nd Amendment IS an unalienable right.