Gas piston operated upper receiver system
First Claim
1. An upper receiver assembly for use with an AR15-type lower receiver in which the lower receiver attaches to an upper receiver assembly by way of a forward pivot pin and a rearward takedown pin, comprising:
- a monolithic upper receiver and forearm housing configured for operable mating engagement with a lower receiver assembly, the upper receiver and forearm housing including a first lug for connection to the lower receiver using the takedown pin;
a barrel having a breech end, a muzzle end, and a bore axis;
a barrel trunnion at the breech end having a second lug for direct connection to the lower receiver using the pivot pin;
a gas block positioned on the barrel;
a bolt carrier assembly including a longitudinal slot and rail engagement with the upper receiver assembly on which the bolt carrier assembly slidably reciprocates;
a long-stroke gas-piston actuation system having a longitudinal axis parallel to and offset from the bore axis, the gas actuation system including a gas tube extending rearwardly from the gas block and a piston extending forwardly from the bolt carrier assembly; and
a recoil spring assembly housed within the monolithic upper receiver and forearm housing and extending coaxially with the longitudinal axis of the gas-piston actuation assembly,wherein the barrel trunnion is configured for engagement with the upper receiver and forearm housing with longitudinal keyway features, one of a keyway or engagement rail being on the barrel trunnion and the other on the upper receiver and forearm housing; and
wherein the gas block is configured for engagement with the upper receiver and forearm housing with longitudinal keyway features, one of a keyway or engagement rail being on the gas block and the other on the upper receiver and forearm housing.
1 Assignment
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Accused Products
Abstract
Disclosed is an upper receiver assembly for use with an AR15-type lower receiver. The upper receiver assembly includes a monolithic upper receiver and forearm housing. A barrel has a breech end, a muzzle end, a bore axis, and a barrel trunnion at the breech end having a lug for direct connection to the lower receiver using the pivot pin. It includes a bolt carrier assembly, having a longitudinal slot and rail engagement with the upper receiver housing on which the bolt carrier assembly slidably reciprocates, and a long-stroke gas-piston actuation system. A recoil spring assembly is housed within the monolithic upper receiver and forearm housing and extends coaxially with the longitudinal axis of the gas-piston actuation assembly. The barrel trunnion and gas block are configured for engagement with the upper receiver and forearm housing with longitudinal keyway features.
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Citations
18 Claims
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1. An upper receiver assembly for use with an AR15-type lower receiver in which the lower receiver attaches to an upper receiver assembly by way of a forward pivot pin and a rearward takedown pin, comprising:
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a monolithic upper receiver and forearm housing configured for operable mating engagement with a lower receiver assembly, the upper receiver and forearm housing including a first lug for connection to the lower receiver using the takedown pin; a barrel having a breech end, a muzzle end, and a bore axis; a barrel trunnion at the breech end having a second lug for direct connection to the lower receiver using the pivot pin; a gas block positioned on the barrel; a bolt carrier assembly including a longitudinal slot and rail engagement with the upper receiver assembly on which the bolt carrier assembly slidably reciprocates; a long-stroke gas-piston actuation system having a longitudinal axis parallel to and offset from the bore axis, the gas actuation system including a gas tube extending rearwardly from the gas block and a piston extending forwardly from the bolt carrier assembly; and a recoil spring assembly housed within the monolithic upper receiver and forearm housing and extending coaxially with the longitudinal axis of the gas-piston actuation assembly, wherein the barrel trunnion is configured for engagement with the upper receiver and forearm housing with longitudinal keyway features, one of a keyway or engagement rail being on the barrel trunnion and the other on the upper receiver and forearm housing; and wherein the gas block is configured for engagement with the upper receiver and forearm housing with longitudinal keyway features, one of a keyway or engagement rail being on the gas block and the other on the upper receiver and forearm housing. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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Specification