resilient member 252 the outer diameter 260 of the resilient member 252 may 90 99 5 the inner diameter of the barrel 214 or preferably 94 99 the inner diameter of the barrel 214 in this particular embodiment the outer diameter 260 of the resilient member 252 is 98 7 the inner diameter of the barrel 214 and the length of the resilient member is about 0 236 inches 6 0 mm in the third embodiment as shown in fig1 the central tube 226 includes a first restriction member 230 in this embodiment the inner diameter of the barrel 214 is 2 28 inches 5 79 cm and the total length of the ball bat 210 is 32 inches 81 3 cm in this embodiment the first restriction member 230 has a diameter of about 2 03 inches 5 16 cm to the surface of the restriction member groove 254 and a diameter of about 2 08 inches 5 28 cm to the tips of the projections 256 a first resilient member 262 is disposed about the first restriction member 230 in the restriction member groove 254 and has an outer diameter 260 of about 2 21 inches 5 61 cm the second restriction member 232 has a length of about 0 3 inches 7 6 mm the first restriction member 230 is located along the length of the central tube 26 at about the same longitudinal station as the center of the optimal hitting area or u201c sweet spot u201d of the ball bat 210 in this embodiment the first restriction member 230 is located about 6 75 inches 17.