Troubleshoot

[LRRPF52]

Sounds like there isn't a gas circuit. Even with a loose carrier key, you will have almost normal cycling, at least in a 5.56 gun. Even if the case seized in the chamber, the bolt would be thrust to the rear by a proper gas circuit, with the extractor just slipping off the cartridge rim.

My best guess: Gas block not aligned with gas port, or gas tube not aligned with gas port. Either way, something ain't right.