Selectable dual mode trigger for semiautomatic firearms

What is this patent about?

’881 is related to the field of semi-automatic firearm trigger mechanisms, specifically those designed to increase the rate of fire through a binary action. In standard semi-automatic systems, a single round is discharged upon a trigger pull, and the hammer is caught by a disconnector until the trigger is released and reset. The invention addresses the limitations of prior rate-increasing devices, such as recoil-dependent stocks or complex external cranks, which often suffer from poor reliability, non-intuitive operation, or safety issues like hammer follow.

The underlying idea behind ’881 is to integrate a user-adjustable cam directly into the trigger body to selectively alter the mechanical timing of the disconnector. By rotating an external lever, the user shifts a camming surface that physically tilts the primary disconnector. This tilting action reduces the depth of the disconnector's engagement with the hammer, allowing the hammer to be released prematurely during the trigger’s return stroke—before the primary sear can catch it—thereby initiating a second discharge upon release.

The claims of ’881 focus on a trigger assembly featuring a rotatable selector cam that passes through a bore in the trigger itself, extending from the internal action to the exterior of the firearm. The independent claim specifically protects the mechanism where this selector acts directly upon a pivotal disconnector to vary its engagement with the hammer. This configuration allows the user to toggle between a standard semi-automatic mode and a binary mode where rounds are fired on both the pull and the release of the trigger.

In practice, the system utilizes a secondary disconnector to ensure the firearm remains legally and mechanically distinct from an automatic weapon. While the primary disconnector is responsible for the binary fire timing, the secondary disconnector acts as a safety catch. If the trigger is held in a partial or 'neutral' position where neither the main sear nor the primary disconnector can secure the hammer, the secondary disconnector grabs the hammer to prevent it from following the bolt forward and causing an unintentional discharge.

This implementation differs from prior art by housing the entire selection mechanism within the trigger group rather than relying on external add-ons or permanent modifications. By using a raised camming surface to precisely control disconnector geometry, the invention provides a reliable way to double the rate of fire that is compatible with common platforms like the AR-15. The result is a system that maintains a traditional manual of arms while offering a mechanical solution to firing speed that is independent of ammunition recoil or external hardware.