I had an A300 for about 6 years, and for the most part it was a great gun and really reliable. I used it steady for waterfowl in the fall and skeet shooting all summer.
After about 3-4 years it developed a breach lock issue that started to deform and caused the bolt to not fully close randomly which made for often light strikes. What finally killed the gun after about 6 years, was the barrel would no longer stay tight in the gun after a few shots. Everything would be cleaned and tight, and a few shots later the barrel was completely loose in the receiver and gas port.