Why cut it at all, In a heavy bullet such as the 100g for .243, you need both velocity, and twist to stabilize the bullet, how ever if cutting short then a heavier bullet may tend not to stabilize fully and yaw its way to the target, accuracy wise you should notice no real difference at normal ranges, but velocity will be any where between 20 and 50 feet per sec down per inch cut off....
i'm extending my barrel length on the build from 22 to 24.5" for added velocity, also long range varminting where velocity is necessary to keep bullet drop minimal...
i would chop to 22" personally if