US Patent 12025404 System for pivoting a buffer tube assembly

A firearm assembly includes an upper receiver housing a bolt carrier group that is translatable within the upper receiver, and a lower receiver including a first hinge portion defining a first hinge opening. A second hinge portion is pivotally connected to the first hinge portion, and a buffer assembly is attached to the second hinge portion. A carrier block is positioned within the first hinge portion and is configurable in a blocking configuration and an unblocking configuration. The second hinge portion is in mechanical communication with the carrier block when the second hinge portion is configured in a folded position. At least a portion of the carrier block is positioned within the first hinge opening when the carrier block is in the blocking configuration. The carrier block prevents translation of the bolt carrier group when the carrier blocking member is in the blocking configuration.