Firearm Casing Curved-Contour Cannelure and Composite Construction
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Solution Overview
Problem
Existing ammunition cartridges face challenges in being lightweight, cost-effective, corrosion-resistant, and durable, while also being difficult to reuse and recycle, with prior materials like brass being costly and other alternatives lacking desirable characteristics.
Innovation Solution
A cartridge design featuring a casing made of austenitic stainless steel with a magnetic property when cold-worked, combined with a softer aluminum alloy base, which allows for improved structural integrity, increased volume for gunpowder, and ease of retrieval using magnets, along with specific seals and shapes to enhance performance and reusability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional brass casings are used, then structural strength and durability are maintained, but cost increases and weight increases
Solution Approach 1:
The patent employs a composite construction with a steel sleeve and aluminum alloy base. The steel sleeve provides the necessary structural strength and pressure resistance, while the lighter aluminum alloy base reduces overall weight. This composite approach allows the cartridge to achieve both strength and weight reduction compared to traditional monolithic brass casings.
Solution Approach 2:
The casing is divided into two distinct segments: a steel sleeve portion and an aluminum alloy base portion. This segmentation allows each material to be optimized for its specific function - the steel sleeve for strength and the aluminum base for weight reduction - while maintaining overall structural integrity through proper interface design.
2Reliability
If traditional brass casings are used, then durability is maintained, but manufacturing cost increases
Solution Approach 1:
Using steel and aluminum alloy instead of traditional brass allows for potentially lower manufacturing costs while maintaining durability. The materials can be formed through different processes (steel sleeve formed and inserted into aluminum base), and the combination provides equivalent or superior durability to brass at a lower cost.
Solution Approach 2:
The patent changes the material parameters from traditional brass to steel/aluminum composite, which alters the manufacturing approach but maintains or improves durability. The material parameter change enables cost-effectiveness while preserving the required mechanical properties for reliable firearm operation.
3Object-affected harmful factors
If brass casings are used, then corrosion resistance is achieved, but weight and cost increase
Solution Approach 1:
The steel sleeve provides corrosion resistance through proper material selection and protective coating, while the aluminum alloy base also offers corrosion resistance. This composite approach achieves equivalent or superior corrosion protection to brass at a lower weight and cost.
Solution Approach 2:
The patent replaces the traditional brass material system with a steel/aluminum composite system that achieves similar corrosion resistance through different mechanisms - potentially through surface treatments, coatings, or the inherent properties of the base materials - thereby reducing weight and cost.
4Strength
If brass casings are used, then structural integrity is maintained, but reusability and recyclability decrease
Solution Approach 1:
The segmented design with removable components facilitates disassembly and reassembly for reloading purposes. The steel sleeve can be separated from the aluminum base, allowing for primer and powder replacement while maintaining structural integrity through proper reconnection.
Solution Approach 2:
The patent design enables easy separation and recovery of components for reloading. The modular construction allows the steel sleeve and aluminum base to be recovered and reused, with the ability to replace consumable items like primers and powder, thereby improving reusability compared to traditional single-use brass cartridges.
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 results in a stronger, more durable cartridge that can withstand high pressures, is easier to manufacture and recycle, and provides improved performance and reusability, while being lighter and more cost-effective than traditional brass cartridges.
Implementation Method 1
austenitic stainless steel with a magnetic property when cold-worked
Data Source
AI summary
A casing for use in a cartridge for a firearm comprises a sleeve portion and a base portion, where the base has cannelure comprised of curving surfaces. In a casing embodiment, a sleeve has cylindrical portion with a mouth for holding a bullet and an opposing end radially-running bulkhead. A nipple extends from the bulkhead and into a passageway of the base, thereby securing the sleeve to the base. The sleeve bulkhead preferably has at least one circumferential wave and contacts a distal end surface of the base, which may be planar or conical. The cannelure is characterized by a continuously curving groove bottom, a maximum groove depth diameter that is 60 to 80 percent of the base outside diameter, and a volume that is 20 to 43 percent of the volume of a like base which has no cannelure.