heres a quote from trueflights website

Do "Round Back" (or "Parabolic") and "Shield Back" fly differently?[blockquote] We haven't been able to detect any difference in the performance of round back or shield back. It appears that the only difference is one of appearance. Round back are more popular in the United States; shield back are more popular in Europe.[/blockquote]

http://www.trueflightfeathers.com/faq.htm
[align=left]hope that helps.......
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