Bottleneck Cartridge Case Geometry for Short-Action Magnum Performance
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Solution Overview
Problem
Existing firearm cartridges are limited by dimensional constraints due to gun powder and firearm action characteristics, leading to a lack of performance variability and economic barriers for new cartridge development, with traditional cartridges often being either small or large, leaving a gap in performance options.
Innovation Solution
A short action cartridge case design with a rebated rim and frusto-conical shoulder, allowing for a higher powder capacity and performance without requiring a long action case, featuring a bottleneck shape and specific length-to-diameter ratios for various caliber projectiles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a long action case is used to increase powder capacity, then propellant efficiency is improved, but the cartridge overall length increases beyond what is needed for performance
Solution Approach 1:
The patent applies dimensionality change by transitioning from a conventional long-action cartridge design to a short-action cartridge with optimized dimensional ratios. Specifically, the cartridge case length is reduced while maintaining adequate powder capacity through improved case geometry, including a reduced case head diameter and optimized case body dimensions. This allows achieving magnum-level performance in a short-action platform, effectively using dimensional optimization rather than simply extending the action length.
Solution Approach 2:
The patent employs parameter changes by systematically adjusting key dimensional parameters of the cartridge case, including the case head diameter, case body diameter, case length, and neck diameter. These parameters are optimized to achieve the desired powder capacity and performance characteristics while maintaining a short overall length. The specific parameter optimizations include reducing the case head diameter to accommodate shorter action and optimizing the case body dimensions to maintain adequate propellant volume.
2Power
If a magnum cartridge is used to increase performance, then muzzle velocity and power are improved, but the action length requirement increases significantly
Solution Approach 1:
The patent applies dimensionality change by creating a short-action cartridge that achieves magnum-level performance through optimized dimensional ratios rather than extended action length. The cartridge case is designed with specific dimensional characteristics, including a reduced case head diameter and optimized case body dimensions, that allow adequate powder capacity within a short action platform. This enables the system to achieve high power and velocity without requiring the traditionally long action associated with magnum cartridges.
Solution Approach 2:
The patent employs parameter changes by optimizing the dimensional parameters of the cartridge case to achieve magnum performance in a short-action configuration. Key parameters including case head diameter, case body diameter, case length, and neck diameter are systematically adjusted to maintain adequate propellant capacity and achieve desired muzzle velocity while keeping the overall cartridge length suitable for short-action firearms.
3Ease of manufacture
If a standard cartridge design is used, then manufacturing simplicity is maintained, but performance variability is limited
Solution Approach 1:
The patent employs parameter changes by optimizing the dimensional parameters of the cartridge case to achieve superior performance characteristics. The case is designed with specific dimensional ratios and proportions that enhance powder capacity and combustion efficiency while remaining compatible with existing manufacturing processes. The optimized parameters include case head diameter, case body dimensions, and neck dimensions, which are tuned to achieve enhanced performance without requiring entirely new manufacturing tooling.
Data Source
AI summary
A firearm cartridge case includes a short action cartridge case comprising a cartridge case main body portion and a cartridge case neck portion that are interconnected by a frusto-conical shoulder portion to form a bottleneck shape, a length L1 of the cartridge case between a base of a rebated rim and an interface between the cartridge case main body portion and the frusto-conical shoulder portion, a ratio of the length L1 of the cartridge case and a length of a projectile receivable within the cartridge case neck portion is between 3.5-0.9.