Bowling ball manufacturing - GIF

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Does anyone here know why the initial plug is asymmetrical? Does that contribute to the spin; does it counter the material loss drilling the holes; is it balanced out by the second layer?
Or is it one of those things that if you told me you would have to kill me?

The stub on the core presumably ends up being the location of the thumb hole. My guess is that the asymmetrical shape forces the ball to spin on that axis when thrown, allowing the bowler to control the path of the ball with the angle of their thumb.

Not an expert opinion. My pathetic bowling scores will never be a matter of national security, so there's that.