Remus your problem is with your team mate not the equipment. You can put a turkey leg inside todays bowling balls and still come out with the same specs as most of whats on the market.
The core doesn't matter. Look at the core specs. The Rg and dif and see how it compares to everything out there. All balls have to stay within USBC regulations.
In some cases with a lot of balls we have seen over the years you can have a core too strong for the coverstock which usually doesn't end well. That happens with every company out.
Your an old school way of mind that doesn't believe in someone needing a lot of equipment to score on most shots. Most people have gone away from that with the power style of bowlers. They think there is a magic ball or drill pattern for every lane condition.
If you team mate wants to keep throwing new equipment and struggle thats between you and him and has nothing to do with the equipment. He will probably do it with anything he throws if he doesn't practice more with said ball, and learn when is best to use it and how to adjust.
That applies to any bowling ball, bowler, and sport out their.
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