The Smallest Minority on earth is the individual. Those who deny individual rights cannot claim to be defenders of minorities. - Ayn Rand
Every so often, you run across something that just refuses to be fixed. There may be some oddball little thing that would make it all right, or it may continue to spring something new every time you find a fix for the previous problem.
I think it was Kenny Jarret said that every so often they'd make a receiver that just would not shoot well, no matter what they did. So now when they run into one of those they cut it in two. Both so nobody will wind up with it and so they won't be tempted to mess with it any more.
Sorry I haven't been following this too closely, but what is your trigger pull weight? I turned my Winchester Model 70 .270WSM into a 3/4 MOA rifle by bringing trigger pull down to 3-3.25 pounds (from factory 6.5 pounds with 1.25 MOA).
Sounds like you need some upward pressure on the barrel at the forend tip? To find out if this helps, and how much is needed, you can slowly build up the bottom of the barrel channel at the forend tip with narrow (about 3/8") strips of black electrical tape an inch or so long. Add a strip, shoot a group, add a strip, shoot a group, etc. Not the most elegant solution, but it's quick, easy, and cheap, you can do it in one range session at the range, and if you hit the sweet spot you can just leave the tape there permanently. Just be sure you're getting the stock/action reseated uniformly and the action screws torqued the same between groups.
If leaving the tape in the barrel channel offends you (it does me) you can put an equal number of layers of tape in the channel in front and in back of your taped up pressure point, remove the tape pressure point and fill in with bedding compound, bolt the barreled action back in as usual and let 'er set up, then remove the tape and trim up the bedding (it should only touch about 1/4 of the circumference of the barrel, not going too far up the sides).
Above all, don't get frustrated and give up! The techniques you learn and try may not work on this rifle, but you're building your bag o' tricks and learning new techniques that will come in handy in the future. It's nice to have rifles that shoot very accurately, but the problem children provide endless excuses for more tinkering, reloading, and range work -- that's not a bug, it's a feature!
RKV: Trigger pull weight is about 2.5 lbs. It's a target rifle, after all. Swen, read this. It details the history of this rifle.