Re: Anyone care to enlighten us all about what 'miltiary grade' chips are?
What the other commenters have failed to mention about "military grade" is that often they are much more more concerned about rf emissions. (Think TEMPEST.)
Military grade: package hardened against extremes of temperature, acceleration, strain, and TEMPEST. There is also a good chance that any back door access lines are terminated well inside the package. Maybe not all at once, but likely.
In practice, these are not generally available with cutting edge technologies.