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: A magazine for a firearm may include a cavity that is shaped to prevent the tip of the bullets in the cartridges from contacting the magazine when the firearm recoils. The magazine may also be configured so that the cartridges in the magazine exit the cavity at least approximately in the center of the magazine. The magazine may be configured to include a biasing mechanism that pushes the cartridges upward in the cavity. The biasing mechanism may be configured to allow the magazine to be compact, simple, and reliable.

Abstract: A magazine for a firearm may include a cavity that is shaped to prevent the tip of the bullets in the cartridges from contacting the magazine when the firearm recoils. The magazine may also be configured so that the cartridges in the magazine exit the cavity at least approximately in the center of the magazine. The magazine may be configured to include a biasing mechanism that pushes the cartridges upward in the cavity. The biasing mechanism may be configured to allow the magazine to be compact, simple, and reliable.

Abstract: A magazine for a firearm may include a cavity that is shaped to prevent the tip of the bullets in the cartridges from contacting the magazine when the firearm recoils. The magazine may also be configured so that the cartridges in the magazine exit the cavity at least approximately in the center of the magazine. The magazine may be configured to include a biasing mechanism that pushes the cartridges upward in the cavity. The biasing mechanism may be configured to allow the magazine to be compact, simple, and reliable.

Abstract: A magazine for a firearm may include a cavity that is shaped to prevent the tip of the bullets in the cartridges from contacting the magazine when the firearm recoils. The magazine may also be configured so that the cartridges in the magazine exit the cavity at least approximately in the center of the magazine. The magazine may be configured to include a biasing mechanism that pushes the cartridges upward in the cavity. The biasing mechanism may be configured to allow the magazine to be compact, simple, and reliable.

Abstract: A magazine for a firearm may include a cavity that is shaped to prevent the tip of the bullets in the cartridges from contacting the magazine when the firearm recoils. The magazine may also be configured so that the cartridges in the magazine exit the cavity at least approximately in the center of the magazine. The magazine may be configured to include a biasing mechanism that pushes the cartridges upward in the cavity. The biasing mechanism may be configured to allow the magazine to be compact, simple, and reliable.

Abstract: A magazine for a firearm may include a cavity that is shaped to prevent the tip of the bullets in the cartridges from contacting the magazine when the firearm recoils. The magazine may also be configured so that the cartridges in the magazine exit the cavity at least approximately in the center of the magazine. The magazine may be configured to include a biasing mechanism that pushes the cartridges upward in the cavity. The biasing mechanism may be configured to allow the magazine to be compact, simple, and reliable.

Abstract: A magazine for a firearm may include a cavity that is shaped to prevent the tip of the bullets in the cartridges from contacting the magazine when the firearm recoils. The magazine may also be configured so that the cartridges in the magazine exit the cavity at least approximately in the center of the magazine. The magazine may be configured to include a biasing mechanism that pushes the cartridges upward in the cavity. The biasing mechanism may be configured to allow the magazine to be compact, simple, and reliable.