Abstract: Firearm sight systems have an elongated mounting rail including a plurality of transverse bars separated by intervening transverse mounting location channels extending from a rearmost channel to a forwardmost channel, the rail having an elongated upper surface, the rail defining a pocket below the upper surface and at least in part forward of the rearmost channel, and a sight arm pivotally connected to the rail and movable between an elevated position angularly offset from the upper surface of the rail and a stowed position in which the sight arm occupies the pocket. At least a forward portion of the sight arm may be entirely below the upper surface of the rail when in the stowed position. The entire sight arm may be entirely below the upper surface of the rail when in the stowed position. The sight arm may pivot on a pivot axis below the upper surface of the rail.

Abstract: Firearm sight systems have an elongated mounting rail including a plurality of transverse bars separated by intervening transverse mounting location channels extending from a rearmost channel to a forwardmost channel, the rail having an elongated upper surface, the rail defining a pocket below the upper surface and at least in part forward of the rearmost channel, and a sight arm pivotally connected to the rail and movable between an elevated position angularly offset from the upper surface of the rail and a stowed position in which the sight arm occupies the pocket. At least a forward portion of the sight arm may be entirely below the upper surface of the rail when in the stowed position. The entire sight arm may be entirely below the upper surface of the rail when in the stowed position. The sight arm may pivot on a pivot axis below the upper surface of the rail.

Abstract: Firearms have an alignment element configured to connect to the barrel with the threaded muzzle portion exposed forward of the alignment element, the alignment element having a lock element movable between a release position and an engaged position, a muzzle device having internal threads configured to mate with the threaded portion of the barrel, the muzzle device defining a lock channel adapted to receive the lock element in the engaged position, the lock channel including wall portions configured to contact the lock element in the engaged position to prevent rotation of the muzzle device, and the lock element in the release position being clear of the lock channel to enable the muzzle device to rotate for removal from the threaded muzzle portion. The alignment element may define a first bore portion configured to closely receive a selected barrel portion immediately aft of the shoulder surface.

Abstract: Firearms have an alignment element configured to connect to the barrel with the threaded muzzle portion exposed forward of the alignment element, the alignment element having a lock element movable between a release position and an engaged position, a muzzle device having internal threads configured to mate with the threaded portion of the barrel, the muzzle device defining a lock channel adapted to receive the lock element in the engaged position, the lock channel including wall portions configured to contact the lock element in the engaged position to prevent rotation of the muzzle device, and the lock element in the release position being clear of the lock channel to enable the muzzle device to rotate for removal from the threaded muzzle portion. The alignment element may define a first bore portion configured to closely receive a selected barrel portion immediately aft of the shoulder surface.

Abstract: A firearm sight system is provided having a mounting rail with an upper surface. The mounting rail defines a pocket below the upper surface. A sight arm is pivotally connected to the rail and movable between an elevated position angularly offset from the upper surface of the rail and a stowed position in which the sight arm occupies the pocket and does not protrude above the upper surface of the rail.