Subsonic Polymeric Cartridge with Volume-Reducing Insert
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Solution Overview
Problem
Traditional subsonic ammunition faces issues with inconsistent propellant burn, reduced accuracy, and inability to efficiently cycle semi-automatic or fully automatic weapons due to the empty volume in the propellant chamber, which leads to variations in velocity and potential weapon jamming.
Innovation Solution
A subsonic ammunition design featuring a polymeric casing with a propellant insert that reduces the internal volume of the propellant chamber by 25-80% compared to standard casings, along with a primer insert and a projectile securely fitted to ensure consistent combustion and improved performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the propellant charge is reduced to achieve subsonic velocity, then the velocity is adequately reduced, but the empty volume in the propellant chamber causes inconsistent propellant burn and reduced accuracy
Solution Approach 1:
The patent introduces a propellant chamber insert that creates a localized restricted volume within the propellant chamber. This insert is positioned to restrict propellant flow in specific areas, ensuring consistent burn rates and proper propellant positioning even when the overall propellant charge is reduced for subsonic velocity. The insert modifies the local combustion environment to maintain reliability despite reduced propellant quantity.
2Speed
If the propellant charge is reduced to achieve subsonic velocity, then the velocity is adequately reduced, but the weapon cycling efficiency is compromised due to insufficient gas pressure
Solution Approach 1:
The propellant chamber insert creates a localized restricted volume that concentrates propellant combustion in a specific area. This ensures that even with reduced overall propellant charge, the combustion generates sufficient localized gas pressure to both propel the projectile at subsonic velocities and provide adequate cycling pressure for semi-automatic or fully automatic weapons.
3Reliability
If a propellant chamber insert is introduced to reduce empty volume, then propellant burn consistency is improved, but the device complexity increases
Solution Approach 1:
The propellant chamber insert is constructed from a flexible polymer material that can be formed into the required shape and inserted into the propellant chamber. This flexible insert can be easily molded and assembled, avoiding the need for complex rigid structures or multiple precision-machined components. The polymer insert provides the necessary volume restriction while maintaining ease of manufacture and assembly.
4Weight of moving object
If polymer materials are used for the cartridge casing, then the weight is reduced and cost is decreased, but the structural strength and reliability are compromised
Solution Approach 1:
The cartridge employs a composite construction where the casing is made from high-strength polymer materials that are specifically formulated to withstand the stresses of firing. The polymer material is selected and engineered to provide both lightweight properties and sufficient structural strength, combining the benefits of weight reduction with the necessary mechanical performance for reliable operation.
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
The design enhances the reliability and accuracy of subsonic ammunition by maintaining consistent chamber pressure and reducing the risk of weapon jamming, while also being more cost-effective and lightweight.
Implementation Method 1
a propellant insert positioned in the propellant chamber to reduce the internal volume of the propellant chamber, wherein the propellant chamber has an internal volume that is between 25 and 80% less than the open internal volume of a standard casing of equivalent caliber
Implementation Method 2
a primer disposed in the primer insert in combustible communication with the propellant
Implementation Method 3
a propellant disposed and confined within the propellant chamber... the projectile does not exceed the velocity of 1,200 feet per second at sea level under standard atmospheric conditions when fired
Data Source
AI summary
The present invention provides a subsonic ammunition cartridge including a polymeric casing body comprising a generally cylindrical hollow polymer body having a body base at a first end thereof and a mouth at a second end to define a propellant chamber; a propellant insert positioned in the propellant chamber to reduce the internal volume of the propellant chamber, wherein the propellant chamber has an internal volume that is between 25 and 80% less than the open internal volume of a standard casing of equivalent caliber; and a primer insert positioned at the body base and in communication with the propellant chamber.