A ball bat extending about a longitudinal axis and configured for testing under an accelerated break-in test. The bat includes a barrel portion that includes an inner surface and is formed of a fiber composite material having wall thickness of at least 0.100 inch. The fiber composite material includes at least first and second plies. The first ply includes a first plurality of fibers aligned adjacent to one another and a first resin, and the second ply includes a second plurality of fibers aligned adjacent to one another and a second resin. The inner surface of the barrel portion defines at least one annular groove. The at least one annular groove creates an ABI fuse region of the barrel portion. The ABI fuse region forms a crack initiation location when the bat is subjected to the accelerated break-in test.