Double-Stack Rimfire Magazine Feed Geometry for Jam-Free Loading
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Solution Overview
Problem
Existing ammunition magazines face challenges in achieving high packing density and reliable dispensing of rimmed cartridges due to their conical shape and radially protruding rims, leading to issues like jamming and improper loading.
Innovation Solution
A double stack magazine design with vertically staggered and skewed orientation of rimmed cartridges, featuring angled cartridge feed surfaces and non-linear convergence ribs to ensure proper alignment and reliable feeding, allowing for increased capacity without jams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If rimmed cartridges are stacked vertically in a traditional magazine, then the magazine can store rimmed cartridges, but the packing density is low and the magazine length becomes excessive
Solution Approach 1:
The patent transitions from a single-column vertical stack to a double-column staggered stack arrangement. Cartridges are arranged in two interleaved columns where odd-numbered cartridges are offset laterally from even-numbered cartridges, effectively utilizing three-dimensional space within the magazine body to increase capacity without proportionally increasing length.
Solution Approach 2:
The patent employs a compact double-stack configuration where cartridges are nested in a tightly packed arrangement. The staggered positioning allows cartridges to interlock and utilize the magazine's internal volume more efficiently, similar to nested structures that maximize space utilization.
2Quantity of substance
If rimmed cartridges are stacked in a compact arrangement, then packing density improves, but feeding reliability deteriorates due to jamming and improper loading
Solution Approach 1:
The follower is divided into distinct functional surfaces: a first cartridge feed surface for engaging the upper portion of cartridges and a second cartridge feed surface for engaging the lower portion. This segmentation allows different parts of the follower to handle different aspects of cartridge feeding, improving reliability in compact arrangements.
Solution Approach 2:
The patent applies different geometric characteristics to different regions of the magazine and follower. The cartridge feed surfaces have specific angle ranges (first surface: 0-20 degrees, second surface: greater than first surface angle) optimized for their local function of guiding and presenting cartridges to the firearm, ensuring reliable feeding despite compact packing.
3Quantity of substance
If a double stack arrangement is used to increase capacity, then cartridge storage increases, but cartridge alignment and feeding complexity increases
Solution Approach 1:
The follower is segmented with distinct first and second cartridge feed surfaces positioned at different locations and angles. This segmentation allows the follower to sequentially engage and guide cartridges from different positions in the double stack, managing the complexity of alignment through divided functional surfaces rather than a single complex mechanism.
Solution Approach 2:
The patent optimizes specific geometric parameters of the feed surfaces (angle ranges, relative positions) to automatically guide cartridges into proper alignment as the follower moves. By carefully selecting these parameters, the system achieves reliable feeding from a complex double-stack arrangement without requiring additional active alignment mechanisms.
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 magazine achieves improved packing density, enabling storage of more than twelve rounds, particularly for.22 LR rimfire cartridges, while ensuring reliable dispensing and reducing the likelihood of feeding jams.
Implementation Method 1
a spring disposed in the cavity; a follower moveably disposed in the cavity and biased in an upwards direction towards the top end of the magazine body by the spring
Data Source
AI summary
A double stack magazine for a firearm comprises a tubular magazine body defining a cavity for holding a stack of cartridges, a spring, and a follower biased by the spring for dispensing cartridges from the magazine. The cartridges may be rimmed cartridges in one embodiment arranged in a vertically staggered side-to-side arrangement. The magazine includes a lower double stack section and upper single stack section. The follower includes angled front and rear cartridge feed surfaces each configured to exclusively engage the cartridge stack at alternate times depending on whether cartridges are present in the lower double stack section. The magazine further includes a pair of non-linear cartridge convergence ribs configured to engage the cartridge stack and force the projectile ends thereof together in the upper single stack section to center an uppermost cartridge in the stack for dispensing from the magazine to the firearm for chambering.