A trigger mechanism that can be used in AR-pattern firearms has a hammer, a trigger member, a disconnector, a locking member, and a three position safety selector having safe, standard semi-automatic, and forced reset semi-automatic positions. In the standard semi-automatic position, rearward movement of the bolt carrier causes rearward pivoting of the hammer such that the disconnector hook catches the hammer hook, at which time a user must manually release the trigger member to free the hammer from the disconnector to permit the hammer and trigger member to pivot to the set positions so that the user can pull the trigger member to fire the firearm. In the forced reset semi-automatic position, rearward movement of the bolt carrier causes rearward pivoting of the hammer causing the trigger member to be forced to the set position, the safety selector preventing the disconnector hook from catching the hammer hook, and thereafter when the bolt carrier reaches the substantially in-battery position the user can pull the trigger member to fire the firearm without manually releasing the trigger member. The locking member is pivotable between a first position at which the locking member mechanically blocks the trigger member from moving to the released position and a second position at which the locking member does not mechanically block the trigger member allowing the trigger member to be moved to the released position. The locking member is spring biased toward the first position and moved against the spring bias to the second position by contact from the bolt carrier during forward movement of the bolt carrier as the bolt carrier reaches a substantially in-battery position.

A magazine is provided for a firearm. The magazine comprises a locking mechanism. The locking mechanism has a user interface adapted to enable a user to select between a locked condition and an unlocked condition. The locking mechanism has a rotor movable between a first rotational position when the locking mechanism is in the locked condition and a second rotational position when the locking mechanism is in the unlocked condition. The magazine comprises an elongated shaft connected to the rotor. The magazine comprises a block element connected to the elongated shaft. The block element is adapted to move between a first position when the locking mechanism is in the locked condition in which at least one of firearm operation and magazine extraction are prevented, and a second position when the locking mechanism is in the unlocked condition in which firearm operation and magazine extraction are enabled.

A magazine is provided for a firearm. The magazine comprises a locking mechanism. The locking mechanism has a user interface adapted to enable a user to select between a locked condition and an unlocked condition. The locking mechanism has a rotor movable between a first rotational position when the locking mechanism is in the locked condition and a second rotational position when the locking mechanism is in the unlocked condition. The magazine comprises an elongated shaft connected to the rotor. The magazine comprises a block element connected to the elongated shaft. The block element is adapted to move between a first position when the locking mechanism is in the locked condition in which at least one of firearm operation and magazine extraction are prevented, and a second position when the locking mechanism is in the unlocked condition in which firearm operation and magazine extraction are enabled.

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.

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.

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.

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.