Abstract: A drop-in system for a semiautomatic firearm trigger includes a trigger-locking block, a hump block, a trigger-locking block transfer bar and an axis retainer plate that operate together to enhance the operations of a semiautomatic firearm trigger. The trigger-locking block is pivoted on a firearm safety pin to lock the trigger when the carrier bolt travels rearward, the hump block is pivotally disposed within a trigger cradle on a trigger pin to receive a force of a hammer to rotate rearward to rotate the trigger assembly backward, the trigger-locking block transfer bar slides along carrier bolt guide and rotate the trigger-locking block forward to releasee the trigger, and the axis retainer plate holds the trigger-locking block rotatably in place and limits the rotation of the trigger-locking block.