Abstract: A firearm can include a receiver, a bolt, and a gas block. In certain implementations, the receiver and/or barrel extension includes a locking shoulder, a lug-interface region forward of the locking shoulder, and a channel wall that defines a bolt channel and a bolt-lug raceway rearward of the locking shoulder. In some implementations, the bolt includes a bolt lug. The bolt lug can be sized and shaped to slidably engage the bolt-lug raceway. Additionally, the bolt can be positioned within the bolt channel of the receiver. Further, the gas block can be positioned at the lug-interface region. In some implementations, the gas block is rotatable with the bolt lug. In particular implementations, the gas block includes a raceway plug sized and shaped to block the bolt-lug raceway. The gas block can also include a bolt-lug notch sized and shaped to mate with the bolt lug.

Abstract: Embodiments of the present disclosure relate to trigger mechanisms for firearms. In one aspect of the present disclosure, the trigger mechanism can include a linkage between a striker sear and a main sear to control an amount of force exerted on the main sear by the striker sear. A portion of the force exerted on the striker sear by the striker can be exerted on the main sear through the sear linkage. In another aspect of the present disclosure, trigger mechanisms are described which additionally, or alternatively utilize one or more biasing members to provide a variable trigger pull weight.

Abstract: Embodiments of the present disclosure relate to trigger mechanisms for firearms. In one aspect of the present disclosure, the trigger mechanism can include a linkage between a striker sear and a main sear to control an amount of force exerted on the main sear by the striker sear. A portion of the force exerted on the striker sear by the striker can be exerted on the main sear through the sear linkage. In another aspect of the present disclosure, trigger mechanisms are described which additionally, or alternatively utilize one or more biasing members to provide a variable trigger pull weight.