$100-$200, depending on condition.
Rohm. See link below.
You can find a 22 mag cylinder for a 22 mag revolver mod 21S MIW Germany on eBay. You may also be able to find one through antique sales and antique gun collectors.
Try e-gunparts.com
rohm is an old German import. no value and not too safe to shoot.......
In perfect condition the Rohm RG 23 .22 cal runs from 50-75$ hope that helps
i have a mod tex 22cal lr with a 22 mag interchangeable barrel
20-60 USD or so
About $150 if its in GREAT condition and has both the cylinders .22 and .22 magnum.
No more than 50 USD if new in the box.
Try e-gunparts.com
50-200 USD