Abstract: An automatic or semi-automatic rifle. The rifle has a receiver and a bolt having a striking surface, the bolt enclosed within the receiver. A barrel has a bore, the barrel coupled to the receiver. An indirect gas operating system has a cylinder and a piston, the indirect gas operating system mounted with a mounting structure substantially independent of the barrel. The cylinder is in communication with the bore, and the piston is fitted to the cylinder and disposed for striking the striking surface and displacing the bolt assembly.

Abstract: A firearm having a lower receiver is provided. The receiver is adapted to couple with a plurality of upper receivers having different calibers. The lower receiver comprises a receiver extension having an opening therein. A spring is disposed within the opening. A buffer member is provided having a first portion having an end. The buffer member is coupled to the spring within the opening, wherein the buffer member is movable between a first position where the end is within the opening and a second position wherein the end external to the opening.

Abstract: A modular automatic or semiautomatic rifle. The rifle has a lower receiver assembly having a fire control assembly for firing the rifle. An upper receiver assembly is provided with a frame and a bolt carrier assembly configured for firing bullets of a predetermined caliber. The lower receiver has a mating interface configured for operably joining the lower receiver assembly to the upper receiver assembly, and for operably joining the lower receiver assembly to another upper receiver assembly different from the upper receiver assembly configured for firing bullets of the predetermined caliber. The other upper receiver assembly has a different frame and different bolt carrier assembly configured for firing bullets of a different predetermined caliber.

Abstract: A system for actuating one or more engine valves comprises a lost motion assembly including locking elements to selectively lock and unlock a locking mechanism disposed within a valve train such that motions may be likewise selectively applied to, or prevented from being applied to, one or more engine valves. In an embodiment, the locking elements comprise wedges having at least one wedge inclined surface defined according to a cone frustum and configured to engage an outer recess formed in a housing, the outer recess comprising an outer recess inclined surface also defined according to the cone frustum. The device may comprise a locking mechanism disposed within a housing bore in the housing and a snubber also disposed in the housing bore. Furthermore, the outer recess may be configured to permit movement of the locking element along a longitudinal axis of the housing bore.

Abstract: A firearm having a lower receiver is provided. The receiver is adapted to couple with a plurality of upper receivers having different calibers. The lower receiver comprises a receiver extension having an opening therein. A spring is disposed within the opening. A buffer member is provided having a first portion having an end. The buffer member is coupled to the spring within the opening, wherein the buffer member is movable between a first position where the end is within the opening and a second position wherein the end external to the opening.

Abstract: An automatic or semi-automatic rifle. The rifle has a receiver and a bolt having a striking surface, the bolt enclosed within the receiver. A barrel has a bore, the barrel coupled to the receiver. An indirect gas operating system has a cylinder and a piston, the indirect gas operating system mounted with a mounting structure substantially independent of the barrel. The cylinder is in communication with the bore, and the piston is fitted to the cylinder and disposed for striking the striking surface and displacing the bolt assembly.

Abstract: A firearm having a lower receiver is provided. The receiver is adapted to couple with a plurality of upper receivers having different calibers. The lower receiver comprises a receiver extension having an opening therein. A spring is disposed within the opening. A buffer member is provided having a first portion having an end. The buffer member is coupled to the spring within the opening, wherein the buffer member is movable between a first position where the end is within the opening and a second position wherein the end external to the opening.

Abstract: An automatic or semi-automatic rifle. The rifle has a receiver and a bolt having a striking surface, the bolt enclosed within the receiver. A barrel has a bore, the barrel coupled to the receiver. An indirect gas operating system has a cylinder and a piston, the indirect gas operating system mounted with a mounting structure substantially independent of the barrel. The cylinder is in communication with the bore, and the piston is fitted to the cylinder and disposed for striking the striking surface and displacing the bolt assembly.

Abstract: A firearm having a lower receiver is provided. The receiver is adapted to couple with a plurality of upper receivers having different calibers. The lower receiver comprises a receiver extension having an opening therein. A spring is disposed within the opening. A buffer member is provided having a first portion having an end. The buffer member is coupled to the spring within the opening, wherein the buffer member is movable between a first position where the end is within the opening and a second position wherein the end external to the opening.

Abstract: Systems and methods for actuating engine valves for positive power and engine braking operation are disclosed. The systems may include a self-lashing hydraulic piston slidably disposed in a fixed or rocker arm housing. The hydraulic piston may have an internal cavity in which a motion absorbing piston is disposed. A hydraulic fluid source may communicate with the hydraulic piston bore. A check valve which may be incorporated in a control valve may controls hydraulic fluid supply from the hydraulic fluid source to the hydraulic piston to provide self-lashing operation of the valve actuation system.

Abstract: An automatic or semi-automatic firearm including a trigger having a frame, at least one trigger sear extending from the frame, and a hammer having a hammer pivot axis, a head and at least one hammer sear disposed on a lateral side of the hammer between the hammer pivot axis and the head, wherein the frame includes a pivot axis and the at least one trigger sear includes a trigger sear surface, the at least one trigger sear extending from the frame such that the at least one trigger sear engages a corresponding one of the at least one hammer sear.

Abstract: An automatic or semi-automatic rifle. The rifle has a receiver and a bolt having a striking surface, the bolt enclosed within the receiver. A barrel has a bore, the barrel coupled to the receiver. An indirect gas operating system has a cylinder and a piston, the indirect gas operating system mounted with a mounting structure substantially independent of the barrel. The cylinder is in communication with the bore, and the piston is fitted to the cylinder and disposed for striking the striking surface and displacing the bolt assembly.

Abstract: An automatic or semi-automatic firearm including a trigger having a frame, at least one trigger sear extending from the frame, and a hammer having a hammer pivot axis, a head and at least one hammer sear disposed on a lateral side of the hammer between the hammer pivot axis and the head, wherein the frame includes a pivot axis and the at least one trigger sear includes a trigger sear surface, the at least one trigger sear extending from the frame such that the at least one trigger sear engages a corresponding one of the at least one hammer sear.

Abstract: A system for actuating one or more engine valves comprises a lost motion assembly including locking elements to selectively lock and unlock a locking mechanism disposed within a valve train such that motions may be likewise selectively applied to, or prevented from being applied to, one or more engine valves. In an embodiment, the locking elements comprise wedges having at least one wedge inclined surface defined according to a cone frustum and configured to engage an outer recess formed in a housing, the outer recess comprising an outer recess inclined surface also defined according to the cone frustum. The device may comprise a locking mechanism disposed within a housing bore in the housing and a snubber also disposed in the housing bore. Furthermore, the outer recess may be configured to permit movement of the locking element along a longitudinal axis of the housing bore.

Abstract: Systems and methods for actuating engine valves for positive power and engine braking operation are disclosed. The systems may include a self-lashing hydraulic piston slidably disposed in a fixed or rocker arm housing. The hydraulic piston may have an internal cavity in which a motion absorbing piston is disposed. A hydraulic fluid source may communicate with the hydraulic piston bore. A check valve which may be incorporated in a control valve may controls hydraulic fluid supply from the hydraulic fluid source to the hydraulic piston to provide self-lashing operation of the valve actuation system.

Abstract: An automatic or semiautomatic blackrifle type rifle having a receiver and a bolt carrier movably coupled to the receiver. An action system is connected to the bolt carrier for cycling the bolt carrier in the receiver. A folding butt stock is connected to the receiver, the folding butt stock being both foldable and collapsible.

Abstract: A firearm having a lower receiver is provided. The receiver is adapted to couple with a plurality of upper receivers having different calibers. The lower receiver comprises a receiver extension having an opening therein. A spring is disposed within the opening. A buffer member is provided having a first portion having an end. The buffer member is coupled to the spring within the opening, wherein the buffer member is movable between a first position where the end is within the opening and a second position wherein the end external to the opening.

Abstract: A modular automatic or semiautomatic rifle. The rifle has a lower receiver assembly having a fire control assembly for firing the rifle. An upper receiver assembly is provided with a frame and a bolt carrier assembly configured for firing bullets of a predetermined caliber. The lower receiver has a mating interface configured for operably joining the lower receiver assembly to the upper receiver assembly, and for operably joining the lower receiver assembly to another upper receiver assembly different from the upper receiver assembly configured for firing bullets of the predetermined caliber. The other upper receiver assembly has a different frame and different bolt carrier assembly configured for firing bullets of a different predetermined caliber.

Abstract: An automatic or semi-automatic rifle. The rifle has a receiver and a bolt having a striking surface, the bolt enclosed within the receiver. A barrel has a bore, the barrel coupled to the receiver. An indirect gas operating system has a cylinder and a piston, the indirect gas operating system mounted with a mounting structure substantially independent of the barrel. The cylinder is in communication with the bore, and the piston is fitted to the cylinder and disposed for striking the striking surface and displacing the bolt assembly.