I have a Ruger 21181 10/22 that might have 25 rounds through it. The goal is to replace the barrel with a Gemtech MIST-22 Takedown barrel. (It's a little over 6 month in jail.) I could part with it early but I'd have to keep the takedown block. The Mist does not come with a takedown block. If that interest you, feel free to send me a PM and we can discuss specifics.
On a side note, I'm also planing to replace the stock with a Magpul Hunter Takedown stock so that might be available too.