Abstract: A ball bat, extending along a longitudinal axis. The bat includes a barrel portion, an end cap and a handle portion. The barrel portion is formed of a fiber composite material and includes a proximal region having a continuous single wall construction, a central region and a distal region. The central region includes at least first and second central region walls longitudinally extending from the proximal region, and a distal region includes first and second distal region walls longitudinally extending from the central region. The central region walls and the distal region walls form a first inner barrel wall and an outer barrel wall, respectively. The barrel walls are spaced apart by a first separation. The first separation is unfilled and longitudinally extends over the central region and the first distal region wall. The end cap and the handle portion are coupled to the distal and proximal region, respectively.

Abstract: A method of forming a barrel portion including obtaining a mandrel shaped to define at least an inner surface of a barrel portion of the bat, wrapping a first plurality of layers of fiber composite material about the mandrel, placing a removable material over a first portion of the first plurality of layers, and wrapping a second plurality of layers of fiber composite material over the removable material and the portion of the first plurality of layers not covered by the removable material for form an assembly. The method further includes separating the mandrel from the assembly, inserting an expandable member within the assembly, inserting the assembly into a barrel-forming mold, and molding the assembly in a single molding cycle, curing the first and second layers with the removable material to form the barrel portion of the bat, and removing the removable material and the member from the barrel portion.

Abstract: A ball bat, extending along a longitudinal axis. The bat includes a barrel portion, an end cap and a handle portion. The barrel portion is formed of a fiber composite material and includes a proximal region having a continuous single wall construction, a central region and a distal region. The central region includes at least first and second central region walls longitudinally extending from the proximal region, and a distal region includes first and second distal region walls longitudinally extending from the central region. The central region walls and the distal region walls form a first inner barrel wall and an outer barrel wall, respectively. The barrel walls are spaced apart by a first separation. The first separation is unfilled and longitudinally extends over the central region and the first distal region wall. The end cap and the handle portion are coupled to the distal and proximal region, respectively.

Abstract: A method of forming a barrel portion including obtaining a mandrel shaped to define at least an inner surface of a barrel portion of the bat, wrapping a first plurality of layers of fiber composite material about the mandrel, placing a removable material over a first portion of the first plurality of layers, and wrapping a second plurality of layers of fiber composite material over the removable material and the portion of the first plurality of layers not covered by the removable material for form an assembly. The method further includes separating the mandrel from the assembly, inserting an expandable member within the assembly, inserting the assembly into a barrel-forming mold, and molding the assembly in a single molding cycle, curing the first and second layers with the removable material to form the barrel portion of the bat, and removing the removable material and the member from the barrel portion.