Latch for a rifle

What is this patent about?

’584 is related to the field of firearm compliance mechanisms, specifically for semi-automatic rifles like the AR-15. In certain jurisdictions, rifles with detachable magazines are restricted unless the magazine is “fixed,” meaning it cannot be removed without partially disassembling the firearm. This creates a technical challenge: providing a way to lock the magazine while the rifle is operational, yet allowing for efficient reloading by slightly opening the receivers.

The underlying idea behind ’584 is to utilize the existing geometry of the rifle’s internal components to create a physical interference that is dependent on the state of the receiver assembly. By installing a specialized latch into the space normally occupied by the bolt hold open mechanism, the invention uses the upper receiver itself as a mechanical stop. When the rifle is closed, the upper receiver presses the latch down into a position that physically obstructs the magazine release; when the rifle is “cracked” open, the latch shifts, clearing the path for the magazine catch to move.

The claims of ’584 focus on a movable latch body that is sized to fit within a standard bolt hold open latch slot and features an integrated adjustable set screw. This latch body includes an actuator surface that interacts with the upper receiver and a block surface that selectively prevents the magazine catch from reaching its released position. The independent claims specifically highlight the inclusion of a movable adjustor element that allows the user to calibrate the exact height of the block surface relative to the receiver’s dimensions.

In practice, the invention functions as a gravity- or spring-assisted gate. When the upper and lower receivers are pinned together, the bottom edge of the upper receiver forces the latch downward. In this state, the block surface sits directly behind the magazine catch, making it impossible to press the magazine release button. To reload, the user pulls a takedown pin to slightly pivot the upper receiver away from the lower receiver. This clearance allows the latch to rise, moving the block surface out of the way and restoring the functionality of the magazine release.

This approach differs from prior solutions by incorporating a movable adjustor element to solve the problem of manufacturing tolerances. Because different manufacturers produce receivers with slight dimensional variances, a fixed-dimension latch might fail to lock properly or might jam the action. By using a set screw to establish the precise contact point between the latch and the receiver, the inventor ensures that the magazine remains legally “fixed” across a wide variety of rifle brands and out-of-specification components.