Before JDAM, precision-guided munitions were expensive and limited in quantity. The JDAM guidance kit?. JDAM Precision Strike Bomb –GBU-31 / GBU-32 / GBU-38. Developed jointly by the U.S. Navy and U.S. Air Force and manufactured by Boeing, this kit attaches to existing Mk-80 series bomb bodies, converting them into the GBU-31, GBU-32, and GBU-38 smart munitions.