The Spring Bat is a modern invention. Designed by rebels in the formative years of the United Cities, it's easy to build and designed to have the power to punch through the heavy armour of dominating military forces. It pays for this with short range and poor accuracy.
Spring Bat is a crossbow which uses heavy bolts. It inflicts heavy damage and is very effective even at low levels, but comes with the risk of a deadly misfire against a teammate due to its low accuracy and high damage.