A member over at SupraForums and SupraMania spent a large chunk of money on finding this out. I can't remember the final decision, but I suspect if you search for posts by "Defiant 7M" over on SupraMania you'll get your answer.
The walls aren't very beefy to begin with though. Most people wouldn't recommend boring any more than you must and preferably nothing past .040 over.
More info's available in this thread:
http://www.supramania.com/forums/showthrea...&highlight=bore