Davelefty,
Of the several 6.5 Creedmoors I've owned, two were Rugers, one a Hawkeye and one a RAR Predator. Both shot around .6 at 100 yards for FIVE-shot groups with Hornady factory ammo, right out of the box. The only thing I ever did to either was adjust the trigger (which is indeed really easy on Hawkeyes.)
Did not "break in" either barrel, because played with it a bunch years ago and found it to be pretty much a farce. It was invented byt benchrest shooters so their rifles would shooting a little better before their first match, but just cleaning after the first few range sessions does the same thing. Dunno where you came up with that routine, but have never heard of anything like it before.
The problem might be the rifle, ammo, scope or even your break-in routine. Hard to tell at this point, but my first suspect (after checking all the easy stuff like screw tightness) is generally the scope--a several people have already mentioned.
