Ok, let's get it working. Well I can tell you it isn't because of the shells being over lubricated or it getting too hot after 50 rounds.
Back in the mid 1970's, during a dove hunt, I had the ejector break on a 16 gauge Remington 58, semi automatic. The gunsmith that replaced it said it was a common problem and was caused by the plastic buildup from the barrel getting hot. Advised me to get a brush that would fit the chamber and take the barrel off and brush it out every once in a while. I did that and never had another problem, and I shot that gun a lot at dove and quail. Have 2 barrels for it, a full choke and an improved for the quail. miles
