What you are looking for is the Redfield JR-56 #511106...you may have to do a little searching as they are long out of production...but one is out there hanging on a peg-board covered with dust somewhere...
You can also do a Weaver base and get some Millett engraved rings...I think I have a set if you want to go that way.
I had a 57M and it was a great shooter with Winchester 40 gr. JHPs...
Bob
