ORIGINAL: Mr Cox
I would check the back side of the prop first, I've had several APC props that needed deburring on the back side. This never does seem flat either, I have no idea as to why they make it this way.....?
Traditional props always have a flat back side as far as I know.
So flatten the back and add a thinner washer, that might be enough. And don't forget to balance it, the holes are often off center and it looks like your's is as well...
I've read that APC holes are drilled by them as required to center the hole where the prop will be balanced... don't know if this is true.
somegeek