Multi-Caliber Firearm Bolt Design for Low-Error Caliber Conversion
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Solution Overview
Problem
Switching the caliber of a multi-caliber firearm involves complex component changes, leading to increased device inventory and a higher likelihood of assembly errors, rendering the firearm useless if a single component from an alternative caliber setup is missing.
Innovation Solution
A multi-caliber firearm design that allows for caliber changes by replacing a minimal number of components, including the barrel, bolt, magazine well, and magazine, with a bolt that has variable features and a cartridge retaining notch to ensure correct loading and unloading, and a barrel extension with a recoil slot for recoil management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple components are made interchangeable to enable caliber changes, then the firearm's adaptability is improved, but the device complexity and inventory requirements increase
Solution Approach 1:
The bolt carrier group is designed to be universal across multiple caliber configurations, serving the function of housing and actuating different bolt types. This multi-functional design allows a single bolt carrier group to work with various bolts, barrels, and magazines, reducing the need for multiple specialized components while maintaining caliber conversion capability
Solution Approach 2:
The firearm system is segmented into modular components (barrel, bolt, magazine well, magazine) that can be independently replaced. The bolt itself is segmented with a cartridge retaining notch that can be selectively positioned. This segmentation allows caliber changes by replacing only the necessary components rather than the entire assembly, reducing overall system complexity
2Adaptability or versatility
If more components are made interchangeable, then the firearm's versatility is improved, but the likelihood of assembly errors increases
Solution Approach 1:
The bolt features a locally variable cartridge retaining notch that can be positioned at different locations along the bolt body depending on the cartridge type. This localized adaptation allows the bolt to correctly retain different cartridge lengths while maintaining a consistent overall bolt design, reducing assembly errors by providing clear, caliber-specific retention features without requiring complete bolt redesign
Solution Approach 2:
The cartridge retaining notch is pre-positioned on the bolt at specific locations that correspond to different cartridge types. Before assembly, the appropriate notch position is selected based on the intended caliber, ensuring correct cartridge retention geometry is established in advance. This preliminary configuration prevents assembly errors by making the correct retention geometry obvious before the assembly process begins
3Reliability
If the bolt is exposed more from the bolt carrier, then the cartridge retaining capability is improved, but the bolt complexity increases
Solution Approach 1:
The cartridge retaining function is extracted from the bolt carrier group as a whole and assigned to a specific feature on the bolt itself - the cartridge retaining notch. By taking this retention function out of the general bolt carrier design and placing it directly on the bolt, the system achieves better cartridge control while keeping the bolt structure relatively simple, as the notch is a minimal geometric feature rather than a complex mechanism
Data Source
AI summary
A multi-caliber firearm includes a barrel extension configured to connect to an interchangeable barrel that is selected from at least two predetermined caliber sizes. An interchangeable magazine well receives a magazine that is selected to house cartridges from the predetermined caliber sizes. The magazine well includes a first end facing towards the stock and a second end facing towards the barrel extension. A bolt carrier group includes a bolt carrier and a bolt. A reverse movement unloads a used cartridge from the bolt and a forward movement loads a new cartridge from the magazine. The bolt carrier group receives an interchangeable bolt that is selected to load and unload one of the predetermined caliber sizes. The bolt includes a longitudinal cartridge retaining notch facing towards the magazine. The cartridge retaining notch is configured to retain the new cartridge in the magazine during the reverse movement.