storm dose this a lot. but they also play with the densities also.
I guessing here but on symmetrical core ball. not much of anything. maybe depending on the drilling.
By what I have drilled in the past with my favorite layout 5 x 3.
If I take a ball that has higher density near the pin and place the pin high I get a stronger angular read in the back and more arc with a the core density in the lower half of the ball.
I can achieve the same reaction on each ball by placing the pin below the fingers on the first (arc) and moving the pin 3 to 4" higher with second ball(flip).
they may have a slight difference in look and for the people that build arsenals to move 2 boards or 2 feet different then the ball next in the bag may care more.
it is something that manufactures can do to create revenue based on old technology. it's more about marketing and sales generation than anything else.
so in the end belive what you want but I'm pretty sure you can place 100 of the similar symmetrical cores with any oreentation in the same shell with no labels and they are going to be about the same when drilled for the right reaction. like drill them all for arc. the patterns may range from 5 x 3 to 4 x 6 etc...
the shell is the factor that matters the most. a flip block or no flip block is going to make bigger difference when you take into account the RG and Diff.
a high RG ball is going to get more length than a low RG ball. A decent flip block will be more angular than the last.
given all things as equals; lane oil, length of oil, revs,speed etc... the balls shell is still the biggest factor.
the only time I ever noticed a core playing a bigger role is a strong MB ball.
now I also belive that they are still on the context of the shell limitations. but it's getting close to where the core is at least equal.
about 4 -6 months ago I wrote up a little comparasion between to track Unleashed I had. now mind you, I didn't try and span the whole spectrum with 2 balls but I did noticed that on the same condition and shell surface the core could completely change the reaction of the ball.
I have had two of the same type balls in symetrical with the core flipped( storms) before and it was not that different in retrospect. when I first did it, The few feet difference was a big deal but since then I learned to bowl and I can make the ball do that with adjustment.
so, long rambling incoherent answer short.. not that big of a deal if you have a good driller and know what you want the ball to do.
--------------------
"deserves got nothing to do with it."
-- William Munny
