If you want it bad enough, it will eventually show up on ebay. Patience is the word. And yes, I know how aggravating it can be sometimes. I've watched for two years before something I wanted finally came up at a price I would pay. I have several daily searches. It's important to get the right combo of terms that gets what you want without a ton of things that have nothing to do with a rear sight. You can also be more specific in looking only in "militaria" or "collectibles" or "sporting goods" that's where most gun parts will show up. Do not get overly specific because people don't know what they have. I'd probably use Carcano rear sight. No model number, etc, too specific. That search currently brings up two carcano sights and then related items which show other sights, etc. Just searching Carcano brings up 125 items which isn't that many to look through. I look through a 24 hour window each day so I have about a day to prepare for the end of the auction.