I have a fireball action 300 whisper and thats about as good as it gets just work that shifter pretty good. I used AICS 223 mags to help cure my feeding troubles.
We have found that by removing the ejector pin and extending the notch for the retaining pin so that it can be pushed further out by the spring it will hold the case longer. . . long enough for it to clear the receiver side and be ejected.
Hope that makes sense....it worked for us on most of the problem guns. Frank
Sorry for not updating this sooner. Tried this fix and it cured my problem completely. Ejects reliably now. Thanks Frank.