AR Shotgun Upper Receiver Short-Recoil Conversion
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Solution Overview
Problem
AR rifles are not inherently suitable for using shotgun cartridges due to their design geometry, particularly the dimensions of the magazine well and the travel of the bolt carrier assembly, which makes it difficult to feed rimmed shotgun cartridges automatically.
Innovation Solution
The conversion of an AR rifle to an autoloading AR shotgun using a uniquely designed AR shotgun upper receiver assembly with a short-recoil mechanism and an AR shotgun ammunition detachable magazine assembly, featuring integrated feed ramps and flexible retention features, allows for the reliable operation of standard commercially available shotgun cartridges without the need for a gas operated mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If a gas operated mechanism is used to support autoloading functionality, then automatic loading is achieved, but the mechanism requires a minimum barrel length which is not suitable for short barrel tactical applications
Solution Approach 1:
The patent replaces the gas operated mechanism with a short-recoil operated mechanism. The short-recoil system uses the rearward movement of the barrel and bolt carrier assembly after firing to cycle the action, eliminating the need for a minimum barrel length while maintaining autoloading functionality. This mechanical substitution allows the shotgun to achieve automatic loading without the barrel length constraints of gas operated systems.
2Ease of operation
If the AR rifle upper receiver and detachable magazine are used, then ergonomic controls and operational functionality are achieved, but the design geometry is not suitable for rimmed shotgun cartridges
Solution Approach 1:
The patent segments the shotgun design into distinct components: the AR rifle lower receiver assembly remains unchanged to preserve ergonomic controls, while the upper receiver assembly is modified to accommodate shotgun cartridges. This segmentation allows the ergonomic benefits of the AR platform to be retained while adapting the cartridge feeding and ejection mechanisms for rimmed shotgun ammunition.
Solution Approach 2:
The modified upper receiver assembly serves multiple functions: it maintains compatibility with the AR rifle lower receiver for ergonomic control retention, accommodates rimmed shotgun cartridges in the magazine well, and provides proper feed ramps and ejection ports for shotgun shell geometry. This multi-functionality enables the system to operate as both an AR rifle platform and a shotgun platform.
3Productivity
If the magazine well dimensions are optimized for slender rifle cartridges, then rifle ammunition feeding is efficient, but rimmed shotgun cartridges cannot be fed properly
Solution Approach 1:
The patent applies local quality by modifying specific areas of the magazine well and feed system to accommodate the broader dimensions of rimmed shotgun cartridges. The magazine well is widened at the critical feeding points while maintaining the overall AR rifle configuration, allowing efficient feeding of shotgun shells without compromising the entire magazine design.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables the AR shotgun to function reliably with shorter barrel lengths and maintain the ergonomic controls and operational functionality of the AR rifle platform, while eliminating the complexity and fouling issues associated with gas systems, allowing for efficient loading, firing, and ejecting of shotgun cartridges.
Implementation Method 1
there has arisen a need for a 'short-recoil' type mechanism to support the autoloading functionality
Implementation Method 2
a spring loaded follower to push upwardly on a column of shotgun cartridges
Data Source
AI summary
Disclosed is an autoloading shotgun firearm which shares interchangeable fully compatible modular sub-assemblies, ergonomics, parts commonality, and exterior appearance with the AR rifle platform. Rapidly reversible tool less conversion from rifle to shotgun and vice versa is accomplished by substitution of the AR rifle upper receiver and ammunition detachable magazine with fully compatible shotgun upper receiver and ammunition detachable magazine. Said shotgun utilizes standard rimmed shotgun ammunition via features in the detachable magazine which securely maintain the position and facilitate the feeding of the cartridges during normal operation. No alteration of the AR rifle lower receiver is required. A short-recoil action is integrated into the shotgun upper receiver. The external appearance and functionality of the AR rifle are retained while eliminating the complexity and inherent fouling issues of typical gas systems used in the AR rifle. A short-recoil action also enables the shotgun to function reliably with shorter length barrels.