I bought one when they first came out in '98 IIRC. I milled off the factory mounts, drilled and tapped it for a custom picatinny rail, had it nickel plated and put a fat fluted Lilja barrel on bedded into a Boyds LH thumbhole. Was one of my favorite rifles, took lots of varmints with it. I picked up another off the EE about 3 years ago, and plan to keep that one stock, it came with an extra .920 barrel (can't recall brand) and a Hogue stock. Might bolt those parts on just to see how the barrel shoots.
When these came it, it was just after I converted a .22LR 10/22 to .22WMR, copying the methods of Paul Mole at the time. There was some serious voodoo in that thing and I have most of the parts. There were two blocks under the barrel with guide rods and a spring, with an operating rod down the side of the receiver in a cut, to a slot in the bolt. It actually worked, and by the time I got it tuned and functioning, Ruger came out with the factory version with the tungsten bolt and steel receiver. I shortened the trigger housing too, to get the mag to fit, was that thing ever a labour of love and determination lol.