Trigger groups for semi-automatic firearms have a frame, a hammer connected to the frame and movable between a cocked position and a striking position, the hammer being biased toward the striking position, a trigger element connected to the frame and movable by a user between a forward position and a rearward position, a selector connected to the frame and movable between at least a first position and a second position, a disconnector having a hammer engagement facility adapted to selectably engage the hammer, a disconnector control element movable between a first control position and a second control position, the disconnector being operably engaged to the disconnector control element, the disconnector operable to move in a first range of motion when the disconnector control element is in the first control position, and in a second range of motion when the disconnector control element is in the second control position.

A fire control group has a receiver having opposed sidewalls defining a space configured to receive a fire control group, the opposed sidewalls each defining a pivot pin aperture, the pivot pin apertures being registered with each other, a fire control group including a trigger received in the space, the fire control group defining a transverse pivot pin passage configured to be registered with the pivot pin apertures of the receiver, the fire control group including a pivoting operational element, the fire control group including a pivot pin supporting the pivoting operational element and received in the transverse pivot pin passage and the pivot pin apertures, the firearm having a hand grip aft of the trigger and defining a screw aperture, and a grip screw engaging the hand grip and engaging the fire control group. The grip screw may occupy a medial plane of the firearm.

A fire control group has a receiver having opposed sidewalls defining a space configured to receive a fire control group, the opposed sidewalls each defining a pivot pin aperture, the pivot pin apertures being registered with each other, a fire control group including a trigger received in the space, the fire control group defining a transverse pivot pin passage configured to be registered with the pivot pin apertures of the receiver, the fire control group including a pivoting operational element, the fire control group including a pivot pin supporting the pivoting operational element and received in the transverse pivot pin passage and the pivot pin apertures, the firearm having a hand grip aft of the trigger and defining a screw aperture, and a grip screw engaging the hand grip and engaging the fire control group. The grip screw may occupy a medial plane of the firearm.

Linear trigger mechanisms for firearms include a trigger slide mounted on, and configured to move linearly in relation to a chassis; and a hammer. The trigger slide has a rolling element, such as a pin-mounted roller or a rolling pin, that engages a contact surface on the hammer and thereby restrains the hammer against its spring bias. When the user pulls the trigger to discharge the firearm, the trigger slide moves linearly, causing the rolling element to roll off of the contact surface and thereby release the hammer. The trigger mechanisms can be equipped with a drop safety that rotates in response to an impact between the firearm and the ground, so as to interfere with the movement of the trigger slide and prevent the release of the hammer.

Linear trigger mechanisms for firearms include a trigger slide mounted on, and configured to move linearly in relation to a chassis; and a hammer. The trigger slide has a rolling element, such as a pin-mounted roller or a rolling pin, that engages a contact surface on the hammer and thereby restrains the hammer against its spring bias. When the user pulls the trigger to discharge the firearm, the trigger slide moves linearly, causing the rolling element to roll off of the contact surface and thereby release the hammer. The trigger mechanisms can be equipped with a drop safety that rotates in response to an impact between the firearm and the ground, so as to interfere with the movement of the trigger slide and prevent the release of the hammer.

The present invention relates to an assembly for modifying a rifle to accommodate various calibers of ammunition and method for changing calibers in a rifle using same.

A shockwave impulse disruptor system for use in an underwater firearm. The system includes a barrel having a bore, a muzzle, and at least one barrel port. A housing is external to the bore and defines at least a first gas expansion chamber. The expansion chamber is in fluid communication with the barrel port and has at least one exhaust port. The barrel bore and expansion chamber are flooded when underwater. Propellant gases that push a projectile through the bore are vented through the barrel port to force water from the expansion chamber through the exhaust port and to vent propellant gases. This delays the release of gases to surrounding water and reduces the amount of gas expelled through the muzzle.

A shockwave impulse disruptor system for use in an underwater firearm. The system includes a barrel having a bore, a muzzle, and at least one barrel port. A housing is external to the bore and defines at least a first gas expansion chamber. The expansion chamber is in fluid communication with the barrel port and has at least one exhaust port. The barrel bore and expansion chamber are flooded when underwater. Propellant gases that push a projectile through the bore are vented through the barrel port to force water from the expansion chamber through the exhaust port and to vent propellant gases. This delays the release of gases to surrounding water and reduces the amount of gas expelled through the muzzle.

A trigger mechanism for use in a firearm having a receiver with a fire control mechanism pocket, transversely aligned pairs of hammer and trigger pin openings in the pocket, and a bolt carrier that reciprocates and pivotally displaces a hammer when cycled. The trigger mechanism includes a hammer, a trigger member, and a locking bar. The hammer has a sear notch and is mounted in the fire control mechanism pocket to pivot on a transverse hammer pin between set and released positions. The trigger member has a sear and is mounted in the fire control mechanism pocket to pivot on a transverse trigger pin between set and released positions. The trigger member has a surface positioned to be contacted by hammer when the hammer is displaced by cycling of the bolt carrier, the contact causing the trigger member to be forced to the set position. The locking bar is pivotally mounted in a frame and spring biased toward a first position in which it mechanically blocks the trigger member from moving to the release position, and is movable against the spring bias to a second position when contacted by the bolt carrier reaching a substantially in-battery position, allowing the trigger member to be moved by an external force to the released position.

A trigger mechanism for use in a firearm having a receiver with a fire control mechanism pocket, transversely aligned pairs of hammer and trigger pin openings in the pocket, and a bolt carrier that reciprocates and pivotally displaces a hammer when cycled. The trigger mechanism includes a hammer, a trigger member, and a locking bar. The hammer has a sear notch and is mounted in the fire control mechanism pocket to pivot on a transverse hammer pin between set and released positions. The trigger member has a sear and is mounted in the fire control mechanism pocket to pivot on a transverse trigger pin between set and released positions. The trigger member has a surface positioned to be contacted by hammer when the hammer is displaced by cycling of the bolt carrier, the contact causing the trigger member to be forced to the set position. The locking bar is pivotally mounted in a frame and spring biased toward a first position in which it mechanically blocks the trigger member from moving to the release position, and is movable against the spring bias to a second position when contacted by the bolt carrier reaching a substantially in-battery position, allowing the trigger member to be moved by an external force to the released position.