Composite softball bats allow batters to get more distance and power from their hits. Composite bats are expensive, however, and if they aren't broken in properly you won't get the performance or the durability you're looking for. There are many myths associated with composite bat break-in, but the only sure way to break in a bat without voiding your warranty is to follow these steps.
Breaking in a Composite Softball Bat
Hit 20-30 balls softly off the tee. Only use about 25% of your power with these first hits. Turn the bat slightly after each hit to cover the entire barrel.
Hit at least 100 softballs off the tee with moderate force. Turn the bat and make sure each part of the barrel comes in contact with several balls.
Hit 50-60 balls with full force. The balls can be hit off the tee or they can be thrown by a pitcher. Rotate the bat after each pitch to ensure even break-in along the entire length of the bat barrel.
Use the bat in a few games, but make sure to alternate the bat with another bat for a few days.