Several years back I had a similar experience with my 722 .257 Bob. right after I got it. After installing a new extractor and still having the non-ejection issue I too looked at getting a Sako style extractor installed. Turns out the rim on the brass (W&W +P) was smaller in diameter than spec. by few 1000th's. This was discovered after gunsmith had me try different manf. brass. Federal and Remington cycled without issue. Unfortunately for me I had purchased a bulk supply (500+ rds.) of factory primed W&W +P brass. Gunsmith had me put an aluminum shim (cut from aluminum can) behind the extractor. Voila problem solved.
