In theroy you should be able to hit the ball more with no inserts and just rev tape. With inserts, not all of your energy/force/lift/hit is being transfered into the ball.
I made the switch and have a little bit of thickening of the skin just around the joint but nothing excessive, and i bowl on average 40 to 50 games per week in the off season.
The first few balls i drilled up i went tighter and then i tried a little bigger, but my fingers do swell and shrink.
If you do make the change to no inserts, it requires changes in not just your finger pitches, but also possibley in your thumb. If you maintain the same pitchings in your fingers and thumb as your old grip with inserts you might start to exit the ball too early.
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Timothy @Juniors Pro-Shop
Montreal, Quebec.