Modular adaptive gun

Patent No. US8464454 (titled "Modular adaptive gun") on Jan 14, 2011. The application was issued on Jun 18, 2013.

’454 is related to the field of modular firearm architectures, specifically focusing on pneumatic or gas-operated guns that utilize a split receiver design. In traditional modular systems like the M16, the lower receiver houses the entire fire control group, meaning the trigger and hammer directly strike a firing pin or valve located in the upper receiver. This invention reimagines that interface to decouple the user's trigger feel from the actual mechanical force required to actuate a high-pressure gas valve.

The underlying idea behind ’454 is to use the lower receiver's hammer not as the primary striking force for the valve, but as a kinetic pilot that triggers a secondary, independent firing mechanism located entirely within the upper receiver. By treating the lower hammer as a signal rather than a power source, the inventor allows the upper receiver to maintain its own optimized spring rates and hammer mass for consistent gas release, regardless of whether the lower receiver has a light match trigger or a heavy military-grade trigger.

The claims of ’454 focus on an upper receiver assembly that contains its own internal upper hammer and sear system designed to interface with a standard lower receiver. The independent claims describe a mechanical chain of command where the motion of the lower hammer—released by the user’s trigger pull—physically strikes a component in the upper receiver to trip the upper sear. This release allows the upper hammer to move from a cocked position to a firing position to actuate a gas valve.

In practice, this is achieved through a sliding carriage or intermediate coupler that bridges the gap between the two receivers. When the lower hammer swings upward, it hits the rear of this carriage, driving it forward to displace a lockout link or the upper sear itself. This internal handoff ensures that the energy used to crack open the motive gas reservoir is generated by the upper receiver’s own dedicated springs, providing a consistent discharge velocity that is isolated from the mechanical variations of the lower frame.

This approach differs from prior art by effectively nesting a complete, self-contained firing group within the upper receiver that is slaved to the lower hammer. While traditional designs require the upper receiver to be a passive recipient of the lower hammer's strike, the ’454 invention allows the upper receiver to be a fully autonomous unit. This enables the use of highly specialized pneumatic valves that might require more striking force than a standard lower hammer can provide, all while maintaining compatibility with common modular lower receiver platforms.

How does this patent fit in bigger picture?

Technical Landscape

In the early 2010s when ’454 was filed, modular firearm architectures were typically implemented using a bifurcated receiver system where the lower receiver functioned as the primary control group housing both the trigger and the hammer. At a time when systems commonly relied on the lower receiver to dictate the mechanical firing sequence and timing, the operational characteristics of the firearm were inherently constrained by the specific trigger and hammer configuration of the lower unit. When hardware constraints made it non-trivial to decouple the firing cycle from the specific lower receiver hardware, interchangeable upper receivers were generally limited to passive components such as barrels and bolt carriers, requiring the lower receiver's hammer to directly strike a firing pin to initiate discharge.

Prosecution Position

The disclosed invention represents a technical advancement through an architectural shift that relocates the primary firing mechanism—specifically an upper hammer and upper sear—into the upper receiver assembly. By utilizing the lower receiver's hammer as a mechanical actuator rather than the primary striking force, the system enables a functional integration where the upper receiver’s performance characteristics remain independent of the lower receiver’s trigger tuning. This configuration overcomes the constraint of fixed mechanical dependencies between receiver halves, allowing an upper receiver to maintain a predetermined gas valve operation or firing sequence regardless of the specific lower receiver to which it is mated. The inclusion of a lockout link and carriage assembly further enhances this capability by ensuring the upper firing sequence is only permitted when the mechanical components are in a specific load orientation.

Claims

The patent contains 11 claims, with claims 1, 10, and 11 serving as the independent claims. These independent claims focus on an upper receiver assembly and associated methods for operably interconnecting a lower receiver's trigger and hammer with an upper receiver's hammer and sear to facilitate firing. The dependent claims serve to provide additional structural details and functional components, such as lockout links, carriage mechanisms, charging handles, and gas-operated firing elements.

Key Claim Terms New

Definitions of key terms used in the patent claims.

Term (Source)	Support for Specification	Interpretation
Cocked position (Claim 1, Claim 10, Claim 11)	The upper hammer is movable between a cocked position and a firing position. The retaining position of the upper sear retains the hammer in the cocked position. Movement of the trigger results in movement of the upper hammer from a cocked position to a firing position.	The state of the upper hammer when it is held under tension by the upper sear, prepared to move to the firing position upon release.
Loaded orientation (Claim 1)	The lower hammer is movable between a loaded orientation and a firing orientation. The upper sear moves from the retaining position to the release position in response to the lower hammer moving from the loaded orientation to the firing orientation.	The specific state or position of the lower hammer when it is cocked and ready to be released by the trigger in the lower receiver.
Lower hammer (Claim 1, Claim 10, Claim 11)	The upper receiver cooperatively engages a lower receiver having a trigger and a lower hammer. The lower hammer is movable between a loaded orientation and a firing orientation. The upper sear moves in response to the lower hammer moving from the loaded orientation to the firing orientation.	A component of the lower receiver assembly, typically part of a standard rifle fire control group, that acts as an intermediary actuator to trigger the upper receiver's internal firing mechanism.
Upper hammer (Claim 1, Claim 10, Claim 11)	The upper receiver includes an upper hammer movable between a cocked position and a firing position. The upper hammer is retained in the cocked position by an upper sear. Movement of the trigger results in movement of the upper hammer from a cocked position to a firing position.	A striking component located within the upper receiver that is distinct from the lower hammer and moves between a cocked position and a firing position to initiate a firing sequence.
Upper sear (Claim 1, Claim 10, Claim 11)	The upper sear is movable between a release position and a retaining position, where the retaining position retains the hammer in the cocked position. The upper sear moves from the retaining position to the release position in response to the lower hammer moving from the loaded orientation to the firing orientation. The released lower hammer contacts a portion of the upper receiver to release the upper sear.	A catch mechanism located in the upper receiver that holds the upper hammer in a cocked position and releases it in response to the physical movement or contact of the lower hammer.

Litigation Cases New

US Latest litigation cases involving this patent.

Case Number	Filing Date	Title
4:25-cv-00299	Jun 6, 2025	Abc Ip, Llc V. Harrison Gunworks Llc

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US8464454

Application Number: US13006998A
Filing Date: Jan 14, 2011
Publication Date: Jun 18, 2013
External Links: Slate, USPTO , Google Patents

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