For barrels, if you want cut rifled, I would look at the Krieger or Rock barrels. You may have problems with them fluting a barrel of that contour, would have to check. #4 maybe, #3 I would bet not.
Trigger wise, I would recommend a Jewell personally if you can afford one.
Detachable magazine system would be an HS Precision RUM DM system. Will give you that extra length for seating bullets out where they should be.
I see no problem with that receiver.
Should make a hell of a lightweight rifle. Only other thing I would say would be to consider the 7mm STW, same performance, your already needed a long action and brass will be available forever. May not be the case with the 7mm Dakota.
Course for a big game rifle, its pretty easy to stock pile enough brass for a lifetime!!
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