During its review, Sandia determined that a significant overram of the powder bags into the gun had occurred as it was being loaded and that the overram could have caused the explosion. A subsequent test by the Navy of the overram scenario confirmed that an overram could have caused an explosion in the gun breech. Sandia's technicians also found that the physical evidence did not support the U.S. Navy's theory that an electronic or chemical detonator had been used to initiate the explosion.