Google 721 extractor, some have been able to fit 700 extractors. I had a Sako extractor installed in my 722, my 721 is still working fine. you might want to pull yours and make sure there is no gunk or pieces of rim interfering.
You would think that someone would have made a replacement by now. You might want to check with Gun Parts and Weidners.
This might help.
Posted: August 28, 2007 10:53 PMFlag633784 Refer to Brownell's Gunsmith Kinks #4 p.342...new Rem 7400/7600 extractors are similar...by thinning out the 7400/7600 extractoe to fit the recess in the bolt head and adjusting its tension you will have a working rifle...this kink worked for me and a happy customer put his 721/222 back in the field. no modifications just alittle grinding on an inexpensive part...hope this helps