Polymer Ammunition Primer Insert for Consistent Ballistics

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Solution Overview

Problem

Conventional plastic ammunition cartridges face issues with reliability, consistency, and safety due to insufficient bullet seating, inadequate chamber pressure, and potential casing breakage during firing, which affects performance and safety in military and sporting applications.

Innovation Solution

A two-piece or three-piece primer insert system made from polymer materials, featuring a cylindrical design with a primer insert and a polymeric middle body, where the primer insert is formed from multiple pieces joined using methods like welding or bonding, and the projectile end is coupled to the middle body with a propellant chamber, ensuring consistent pressure and strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If conventional plastic cartridge casings are used, then weight is reduced compared to brass, but reliability and consistency deteriorate due to insufficient bullet seating and inadequate chamber pressure

Engineering Contradiction:

Improvecartridge weightVSAvoidballistic performance consistency

Core Design Contradiction:

Weight of moving objectVSReliability

Solution Approach 1:

The cartridge casing is divided into multiple polymer components (mouth end, middle body, base end) that are separately molded and then joined together. This segmentation allows each component to be optimized for its specific function while maintaining overall structural integrity and consistent ballistic performance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention uses polymer composite materials for the cartridge casing components, combining lightweight properties with enhanced strength and consistency. The polymer materials provide both weight reduction and improved reliability compared to conventional plastics.

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If conventional plastic cartridge casings are used, then manufacturing cost is reduced, but safety deteriorates due to potential casing breakage during firing

Engineering Contradiction:

Improvemanufacturing costVSAvoidcasing breakage

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

Dividing the casing into multiple joined components allows for better stress distribution and controlled failure modes, preventing catastrophic breakage while maintaining cost-effective polymer manufacturing processes.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The multi-component polymer design incorporates built-in structural features that prevent catastrophic failure by distributing stresses throughout the assembled components, cushioning against the harmful effects of pressure spikes during firing.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Weight of moving object

If conventional plastic cartridge casings are used, then weight is reduced, but strength deteriorates leading to insufficient bullet seating and chamber pressure

Engineering Contradiction:

Improvecartridge weightVSAvoidcasing strength

Core Design Contradiction:

Weight of moving objectVSStrength

Solution Approach 1:

Using polymer composite materials provides both lightweight properties and enhanced mechanical strength, allowing the casing to maintain bullet seating and chamber pressure requirements while keeping weight reduced compared to brass.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The segmented design with multiple polymer components allows each part to be optimized for specific strength requirements, with join features that distribute loads effectively throughout the assembly.

Inventive Principle:

Principle #1Segmentation

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 solution provides reliable and consistent ballistic performance, enhances safety by preventing casing breakage, and maintains interchangeability with brass cartridges, addressing the shortcomings of previous plastic ammunition designs.

Implementation Method 1

the primer insert is formed from multiple pieces joined using methods like welding or bonding

Methodology Applied

Scientific EffectWelding: Welding

Implementation Method 2

the primer insert is formed from multiple pieces joined using methods like welding or bonding

Methodology Applied

Scientific EffectBonding: Adhesive

Implementation Method 3

a propellant at least partially filling the propellant chamber

Methodology Applied

Scientific EffectCombustion: Combustion

Data Source

PatentUS9551557B1Polymer ammunition having a two-piece primer insert

Publication Date: 2017.01.24 TRUE VELOCITY IP HOLDINGS LLC

AI summary

The present invention provides ammunition having a two piece primer insert with a flange, a polymeric middle body extending from the primer insert to a cylindrical middle body coupling region, a polymeric projectile end having a projectile aperture mated to the polymeric middle body, a primer inserted into the primer aperture, a propellant at least partially filling the propellant chamber, and a projectile frictionally fitted in the bullet-end aperture.