Also check the length of the ejector, this can lead to all kinds of problems in the AK. (It's somewhat counter intuitive, but in addition to ejecting the empty casings the ejector plays a part in guiding the bolt as it picks up a fresh round.)
- Field strip
- Put the bolt & carrier back in and observe how well the ejector fills the gap in the bolt. If the bolt has a lot of play as it passes next to the ejector, that may be your issue. You want the ejector to fill out the gap while not binding.
Specs to check: (measure from outside of receiver to ejector tip)