The only aluminum bedding blocks that I ever saw that truly fit to thier respective receivers were machined that way. That is, the receiver was trued, then the blocks were machined to match, then they were installed in the stock. Other then that it's a crap shoot, and as Jerry says, just screwing the two components together harder is not the answer. In my opinion, barring a lot of custom machining, bedding is a requirement to achieve the accuracy potential of pretty much any rifle with accuracy intentions. - dan