For the medium patterns with the big backends, i use:
I am a 18.0mph bowler, with a 270average rev rate. PAP: 5"over, 1/2" up.
15# Ebonite V2 Pearl; 3-4" pin. Pin @ 12:00 over the bridge, CG stacked below it @ center of grip.
Even rolling ball with little pop in the backend. Allows the pearlized coverstock to clear the heads and continue an even roll into the pocket. It's not very jerky.
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-Jeremy Vitug
BallReviews.com Burning Sensations Bowling Team