Did you compare the same measurements with your other 7x64 rifles? IMO you're probably making much ado about nothing; it's very common for factory ammo (and even component brass) to have at least .010" headspace in correctly cut chambers.
Yes, my Sako M85 has about .004" headspace and the Steyr Mannlicher about 0.006" Quite different.
If I can make some assumptions from your comment, I think you're talking about headspace as measured with gauges in the chamber. What I'm talking about is actual headspace - the clearance between the cartridge and the chamber, which in the case of handloads has only a little to do with how the chamber compares to a gauge. A good reloader can minimize headspace in almost any chamber, but a lot of factory ammo is undersized to be sure it fits everything, and results in significantly more headspace than what a gauge tells you.
