Use this as a "rule of thumb"...
A ball, with it's core, is designed to weigh so much. When you take away from the design weight, something has to go, as well, when you add to it. Depending on the design weight, as you drop in weight, something will change, since the size of the ball can not, or the 'filler' can not, then the core is the logical point to change.
Fillers weigh just about the same, but some companies have a different core they will use to drop the weight. That doesn't make the ball "bad", just different. If you can only use a 13 #, then your ball will react differently than a 15#, just learn to use what you have, and know that's what the ball can give you. It's not a bad thing, just different.
As in, a 16# will react when it hits the pins differently from a 14# ball of the same kind. Not a bad thing, different. I played with the idea of getting a 12 or 13# spare ball for deflection on spares, just never have....yet. IMO, not bad, just different.
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AZ Guy aka: R & L Bowlers Pro
rlbowlerspro@cox.net
www.rlbowlerspro.comSleep is over rated.