looking to buy extractor ring rem. mod.722..257 rob. all subgestions welcome. thanks.

Try Numrich arms. www.gunpartscorp.com

Or Brownell's
1-800-741-0015
If it is a rivetless extractor, the part number should be 767-918-160AH

Don't think you will find one at the two places listed above,i will give you a person that may have one:
(785)4546361
If that fails call:Roy Gregg(509)697-9000
He mills out the raceway so a 700 rivet type will fit,installs it with the rivet
I have been down this road before,you can have a sako installed,but he is a bit chaper and a safer,better job.
Did yours break or just fit loose and turn in the raceway and won't eject very well?Not sure why,but i have seen more roberts fail or get weak.Also the new rivetless ones(brownells) won't work