Eight-Lug Bolt Carrier for Cone-Breech Feeding Reliability
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Solution Overview
Problem
Semi-automatic firearms, particularly AR-15/M-16 models, face challenges with cartridge feeding due to the interference between cone-breech designs and plunger-style ejectors, leading to jamming and reduced locking lug strength, as conventional tapered bolt configurations are not compatible with repeating firearms.
Innovation Solution
The development of an eight-lug semi-automatic firearm bolt with a tapered breech face and cartridge guide fillets, combined with a wide-flanged extractor design that fits between locking lugs or over an eighth lug, allowing for a cone-breech configuration that accommodates a plunger-style ejector without compromising lug integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cone-breech design with plunger-style ejector is used, then cartridge feeding reliability is improved, but locking lug strength is reduced
Solution Approach 1:
The bolt is divided into multiple locking lugs (seven or eight) that are distributed around the circumference, allowing the extractor to be positioned between lugs or over an eighth lug without compromising the overall locking structure. This segmentation enables the cone-breech design to maintain both feeding reliability and locking strength.
Solution Approach 2:
The locking lugs are asymmetrically positioned around the bolt, with specific spacing that accommodates the extractor mechanism. The eighth lug (when present) is positioned to allow extractor placement without interfering with the primary locking lugs, creating an asymmetric distribution that optimizes both feeding and locking functions.
2Reliability
If a tapered bolt configuration is used, then cartridge feeding is improved, but compatibility with repeating firearms is reduced
Solution Approach 1:
The bolt design with multiple locking lugs and standardized extractor positioning serves dual functions: it provides the tapered configuration needed for reliable cartridge feeding while maintaining compatibility with repeating firearm mechanisms. The universal adapter or barrel extension allows this design to work across different firearm platforms.
Solution Approach 2:
A universal adapter or barrel extension acts as an intermediary component that bridges the tapered bolt configuration with the repeating firearm mechanism. This intermediary allows the cone-breech design to function in semi-automatic and repeating firearms without direct modification to the core bolt structure.
3Reliability
If an eighth locking lug is added, then extractor positioning is improved, but lug material is reduced
Solution Approach 1:
The eighth locking lug is positioned in a specific location where it provides optimal extractor positioning without significantly reducing the material volume of the primary locking lugs. The local addition of the eighth lug creates a dedicated positioning point while maintaining the structural integrity and material distribution of the main locking system.
Data Source
AI summary
Systems, methods, and articles of manufacture for repeating and semi-automatic cone-breech firearm systems, including barrel extension and bolt carrier systems, are provided. A semi-automatic cone-breech firearm system may, for example, comprise a tapered semi-automatic seven (7) or eight (8) lug bolt having a cartridge channel that facilitates engagement of an ammunition cartridge with a cartridge seat and/or a plunger-style ejector and may comprise a barrel extension and mating bolt carrier for housing and accepting the bolt.