Composite bats Jared MacLeod HR.319 My baseball league does not allow certain kinds of baseball bats because they generate far more power than a bat made of aluminum. Composite bats are made out of aluminum and graphite which generates far more power than an all aluminum bat. One good hit with a composite bat and some ones teeth are out. That would be why composite bats are banned in little league play. I personally think these bats should be illegal because it injures some one severely because of how fast the ball can move. Also because I have bad teeth and if anything happens the league is in big trouble.