Polymeric Subsonic Ammunition Propellant Insert
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Solution Overview
Problem
Traditional methods for producing subsonic ammunition result in issues such as inconsistent propellant burn, reduced accuracy, and failure to efficiently cycle semi-automatic or fully automatic weapons due to the empty volume in the propellant chamber, leading to variations in velocity and potential weapon jamming.
Innovation Solution
A method involving a polymeric subsonic ammunition casing with a metal primer insert and a propellant insert that reduces the internal volume of the propellant chamber by at least 10% compared to standard casings, using a cylindrical shape and specific polymer materials like polyphenylsulfone and polycarbonate, to ensure proper propellant positioning and combustion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the propellant charge is reduced to achieve subsonic velocities, then the projectile velocity is reduced to subsonic range, but the empty volume in the propellant chamber causes inconsistent propellant burn and reduced accuracy
Solution Approach 1:
A propellant insert is positioned within the propellant chamber to occupy the empty volume created by reduced propellant charge. The insert is nested inside the chamber, filling the space that would otherwise be vacant and causing propellant movement issues.
Solution Approach 2:
The propellant insert acts as an intermediary element between the reduced propellant charge and the propellant chamber walls. It mediates the interaction by providing a physical presence that prevents propellant movement and ensures consistent burn characteristics.
2Speed
If the propellant charge is reduced to achieve subsonic velocities, then the projectile velocity is reduced to subsonic range, but the empty volume causes reduced chamber pressure and failure to cycle firing mechanism
Solution Approach 1:
The propellant insert is nested within the propellant chamber to reduce the effective chamber volume. By occupying space inside the chamber, it increases the pressure generated by the reduced propellant charge, enabling proper cycling of the firing mechanism.
3Speed
If traditional methods are used to reduce propellant charge for subsonic ammunition, then velocity is reduced, but the empty volume leads to propellant detonation from high burn rates
Solution Approach 1:
The propellant insert serves as an intermediary that stabilizes the propellant charge by preventing movement and ensuring consistent positioning. This mediation eliminates the conditions that lead to erratic burn rates and potential detonation.
4Weight of moving object
If polymer ammunition is used to reduce weight, then the ammunition weight is reduced, but the bullet pull may be too light causing the bullet to fall out or insufficient pressure to cycle the weapon
Solution Approach 1:
The design parameters of the propellant insert are optimized to generate sufficient chamber pressure despite the reduced bullet pull from lighter polymer ammunition. By adjusting the insert geometry and propellant quantity, the system compensates for the reduced forcing power.
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
This solution enhances the reliability and accuracy of subsonic ammunition by maintaining consistent propellant burn and sufficient chamber pressure, improving the cycling of firing mechanisms and reducing the likelihood of weapon jamming.
Implementation Method 1
overmolding a polymer composition over the substantially cylindrical insert by molding the polymer composition over the substantially cylindrical coupling element
Implementation Method 2
forming a propellant insert to reduce the internal volume of the propellant chamber, wherein the propellant chamber has an internal volume that is at least 10% less than the open internal volume of a standard casing of equivalent caliber
Data Source
AI summary
The present invention provides a method of making a subsonic ammunition having a polymeric casing body having 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 at least 10% less than the open internal volume of a standard casing of equivalent caliber; and a primer insert positioned in the body base and in communication with the propellant chamber.