Crossbows having two trigger safety locks. Operatively connected to a trigger is a trigger lock element that in one position prevents the trigger from moving. To prevent inadvertent contact between a cocking slide and a released stretched cord of the crossbow, a slide lock element engages the trigger lock element until the slide lock element is disengaged by the cocking slide moving out of the way. To prevent an improperly configured projectile from being discharged a projectile lock element engages the trigger lock element until a properly configured projectile is loaded onto a drum causing the projectile lock element to disengage from the trigger lock element.