A baseball or softball bat configured to allow the removal and replacement of a barrel assembly of the bat for enabling selection of a barrel having particular performance characteristics or simply if the barrel is damaged. Alternatively, the barrel assembly may be selectively changed to meet certain regulation requirements. In particular, the barrel assembly or other bat component can also include a ballast for selectively providing the ball bat with a particular weight. The ballast can be provided as a tube of thin film in the barrel assembly. The thin film ballast tube also forms a tamper resistant shield to inhibit modification of components inside the barrel section. In one aspect, one or more components of the ball bat can be provided as a kit. In one aspect, the kit may be a barrel assembly kit. In another aspect, the ball bat can be made by forming and assembling the components.