Yea, I've read that it's pretty hit and miss (with more misses than hits) when it comes to placing the rifle and shotgun rounds in the same location. Honestly I doubt I'll be using the .22 rifle bore much, I'm mostly restoring it for the .20 ga shotgun portion. Maybe I'll get to the range this weekend and see whether this one's one of the lucky few that shoot straight.
I kinda wish I'd gotten back here and seen your post a little earlier imr. I dunno if the methods you described would have had the results I would want, but it might've saved me 4 hours worth of cutting, shaping, drilling, tapping, and finally welding a hunk off a busted craftsman wrench to suitably secure the fore end to the barrel. For reference, no I didn't weld anything to the barrel, I welded it to that little tab you were talking about shimming. Either way, here's hoping that I didn't hurt anything with my hillbilly gunsmithing.
For kicks and giggles I'll attach a pic of the modification, and the semi finished product. I need to find a local smith that can knock off the rust and blue the barrel and maybe re do the nickel on the receiver. Or maybe just blue the whole thing, I haven't made up my mind yet.

