Like Kid said, it affects how you can drill the ball. If you wanted the pin in your palm like a Rico drilling, then you would not want a 4-5" pin to CG length because the CG would be under your thumb making your statics way off. Likewise, if you wanted to drill the ball with pin high above your fingers, a 0-1" pin would give you way too much top weight. But with a 2-3" pin, which is probably the most common, you can get away with most if not all drillings. Hope that helps
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Penn State Mens Bowling Team