drilling out a bowling ball

Question
If I wanted to lighten up a ball were would be a good place to start

Answer
Robert,
Even the biggest drill bits don't take much weight out of a ball. You can reduce the weight by ounces. While the effect you are looking for might need to be a pound or more.

A good fit means NO GRIP Pressure. You might want to consider an improved fit rather than working harder with maybe a lighter ball.

Try a house ball. Fits are notoriously BAD. If you have to grip your own ball like a house ball, it's a terrible fit. Your ball weight should be around 10 percent of your body weight. If you are trying to get something lighter because you are working to hard to hold onto it, get the fit adjusted.  Thanks for the question. If I'm miss understanding your intention, please let me know. Good luck.