Brian,
You didn't mention what Federal shell you were using. Gold Medal, Top Gun, Estates, etc.? Is it difficult to close the gun sometimes on a loaded shell? My closet queen 12ga Parker has a difficult time closing and opening on certain types of new shells. Have to force it closed and then break it over my knee to open the gun. I had my gunsmith cut the chamber rim depth just a little deeper. What I've found is some shells have a radius where the rim is formed and others have a more 90 degree shape between the brass wall and the rim.
Gold Medal's use brass bases, the others are steel. Some modern gun chambers don't like steel based hulls and won't extract properly. The steel bases don't retract like brass bases do after firing. I've heard that polishing the chambers can help. I shoot nothing but Federal primers in Estates or Top Guns with no problems so far.
You ought to make a trip to Hausemann's this weekend to chat with the guys
