Split Chamber and Dummy Extractors for CT Ammunition
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Solution Overview
Problem
Firearms designed for cased telescoped ammunition face challenges in extracting cartridges due to the thinner, lighter weight of CT cartridges, which require radial support along their entire length to prevent uncontrolled gas release during firing, and existing extraction mechanisms are not suited for the lower strength of polymer cases.
Innovation Solution
A split chamber design with a dynamic rear chamber portion and a static front chamber portion, along with a cartridge extraction mechanism that includes a pivoting extractor and dummy extractors, provides radial support and engages the CT cartridge before and after firing to ensure proper ejection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional metal case cartridges are used, then the cartridge case has sufficient strength to withstand extraction forces, but the cartridge weight is high and radial support along the entire length is not required
Solution Approach 1:
The patent changes the material parameter of the cartridge case from traditional metal to polymer, which reduces weight but also reduces strength. This necessitates design changes in the extraction mechanism to compensate for the lower strength of polymer cases while achieving weight reduction.
2Device complexity
If a chamber design without full radial support is used, then the structure is simpler, but polymer case material may flow outwards and cause uncontrolled gas release
Solution Approach 1:
The chamber is segmented into multiple sections with varying degrees of radial support. The front portion provides full radial support to prevent polymer flow, while the rear portion allows for extraction. This segmentation enables the chamber to provide necessary support during firing while maintaining structural simplicity.
3Device complexity
If existing extraction mechanisms designed for metal cases are used, then the extraction mechanism is simpler, but they cannot provide adequate grip on lower strength polymer cases
Solution Approach 1:
The extraction mechanism uses a dynamic extractor that can pivot or move to engage the polymer case at multiple points. This dynamic engagement provides adequate grip on the lower strength polymer case during extraction while allowing the mechanism to return to a neutral position after extraction.
4Stability of the object's composition
If the chamber provides full radial support along the entire cartridge length, then polymer case material flow is prevented, but the chamber structure becomes more complex
Solution Approach 1:
The chamber provides local quality in terms of radial support - full radial support is provided in the front portion where polymer flow is most likely to occur, while the rear portion has reduced support to facilitate extraction. This localized approach maintains case integrity where needed without unnecessarily complicating the overall chamber structure.
Data Source
AI summary
A firearm for firing cased telescoped (CT) ammunition cartridges that includes a split chamber configured to fully support a CT cartridge when it is fired, and that includes i) a dynamic rear chamber portion defining a pocket in a face of a bolt, and ii) a static front chamber portion that is integral to the barrel and separate from the bolt. A cartridge extraction mechanism engages the CT cartridge prior to the CT cartridge being fired, and holds the CT cartridge in the pocket in the bolt face as the bolt moves rearward to pull the CT cartridge out of the static front chamber portion and into an ejection position. An ejector is operable to eject the CT cartridge from the pocket in the face of the bolt when the CT cartridge reaches the ejection position.