I was going to SBR my Ruger 10/22 but never did, sold the 10/22 but still have this barrel. If you already have a 10/22 SBR then this would make a great spare barrel.
Made by Cobray in 1993 time frame
Barrel is threaded and includes a dummy silencer
$85 shipped to you in CONUS, paypal add 3%
not sure of the threading on the bbl itself, it does appear to be 1/2" diameter.
The fake silencer adapter has the same threading that a regular AR15 buffer tube has
Here's some closeups if that'll help