The difference between the two standards is actually very simple. The USSSA BPF 1.15 bats will be more lively and will, simply put, hit the ball further and the USA bats.
USABats or USA Baseball approved bats are baseball bats that are certified with barrel diameters of 2-5/8″ and less. Approved USABats come in a barrel diameters including 2-5/8″, 2-1/2″, 2-3/8″, 2-1/4″ and 2″.
USSSA bats have a 1.5 BPF and a larger barrel diameter thus they offer much more pop when hitting the ball.
