National Training Center, Fort Irwin California, Spring 2000. During the live fire defense, my wingman calls me on the radio and says the breech of his main gun fell apart, it was about 4 in the morning, it was dark and I was busy fighting my tank, so I told him that there was nothing I could do about it right then. Well, after the sun comes up, I look over at my wingmans tank and I noticed that the end of his guntube is missing.....I think I know why his breech fell apart. Turns out there was a defect in the guntube, it was bent slightly in the middle, not enough to notice with the eye, but enough to make the rounds hit the top of the tube at the end. When it finally blew, the overpressure forced the gun out of battery (it went all the way into the turret until it hit the back and bounced out) which is why the breech fell apart.