You'll note that they don't make them anymore. This was when Bushmaster first started making things. They were not known for their reliability. Even the gunrags that always give glowing reports for a fee, mentioned many stoppages. They'd pass it off like three or four jams in 100rds was nothing, but they didn't stop making them because they were working great and selling good.
I'm sure there were great working ones as well as the bad ones. They are a collector item to be sure.
Ross