Do core shapes matter? Do you think they make a difference? Not so much the number's but the shape of the core?
It seems to me or at least I got it in my head that they do despite the rg and diff numbers.
What say you?

I think so. Almost all of my favorite balls have had somewhat similar core shapes. Lightbulb shaped and taller cores seem to work well for me, i think it's because of my low axis tilt and lower axis rotation

I'm like a chubby chaser,like the fat round ones.

AFAIHL,
Taller, thinner cores will have a more sudden or hockey shaped breakpoint than will a rounder shaped core, WHEN used with the same coverstock.

That said,
the coverstock rules; so a tall, thin cores used with one coverstock can have a more smooth or urethane-like breakpoint than will a more rounded core when used with a COMPLETELY different coverstock.

Core shape, by itself, can be misleading if densities are not equal throughout the entire core.  However, as a general rule, taller cores (higher RG) will rev up less quickly and do what others ahead of me described. 

Low RG cores, with their weight more inward, will rev easier, and combined with the right cover can be a friend to those who don't have high revs off their hand.  It's usually a good idea to have equipment with a wide variety of cores and cover stocks that compliment what the bowler adds to the ball. 

so big round cores such as the fight don't fit the mold with their core numbers?

How do you mean?

Core shapes, alone, can be misleading if the densities are changed.  If a round core has more dense material outward it would change (raise) the RG. 

Remember that when a manufacturer designs a ball they are usually targeting a certain reaction.  By raising the RG they can hit their desired reaction further down-lane.  For many the higher RG cores kinda "lope" through the front half of lane, and then do their work later. 

Core shape, by itself, can be misleading if densities are not equal throughout the entire core.  However, as a general rule, taller cores (higher RG) will rev up less quickly and do what others ahead of me described. 

Low RG cores, with their weight more inward, will rev easier, and combined with the right cover can be a friend to those who don't have high revs off their hand.  It's usually a good idea to have equipment with a wide variety of cores and cover stocks that compliment what the bowler adds to the ball. 

notclay,

Has Brunswick provided (for public consumption) a matrix for core/coverstock strength?  Recently, one was posted in the Storm/Roto forum, and it was insightful in understanding why my 2 S/RG pieces (iQFusion/Eternal) fit well for my game.  It may help others in addressing your point of having diversity in their arsenals - not just to single out B - all OEMs should do that...

Nice job, sixpack, fascinating topic.

The reason I brought up this topic is I like and do well with the large round cores but they tend to roll to hard for me and lose carry. I try surface changes but sometimes it seems I lose the matchup between core and cover. Most tall cores flip hard for me and I don't tend to keep those types in an arsenal for very long,don't even want to try anymore with those core types. I set up one of my wife's old 14lb. Rotogrip Venus and with its high rg and low diff and a big core in it I love the ball. It motors down the lane and rips the rack without the flippy reaction I can get with tall cores. Of course cover and layout plays a roll.
I thinking of trying the storm fight as over the years almost all my favorite balls had large cores, just a tendency I've noticed over the years.