Printed circle accuracy

Following on from other threads about fixing oval circles, I wondered what sort of accuracy everyone is getting now.
To the naked eye, my circles look pretty good but on closer inspection with calipers, the diameter of every circle I print is as much as 0.4mm short in the Y axis.
This means I have to compensate for this when printing something that needs to have precise measurements and then sand the oversized area.
I've replaced my broken bearing mounts and tightened all belts. I can't see any play in the white pulleys at the back so haven't bothered to shim them.
Is this about as good as it gets or is anyone else getting better accuracy ?