Modular Two-Piece Bolt Assembly for Matching Blowback Ammunition Loads
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Solution Overview
Problem
Bolts used in blowback operated firearms require precise mass matching to propellant powder charges, necessitating multiple bolt fabrication and costly replacements when changing calibers, lacking modularity and economy.
Innovation Solution
A modular two-piece bolt system with interchangeable front and rear pieces, allowing the same rear bolt piece to be used with different mass front pieces to match the propellant powder load, and a standardized design for various calibers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple bolts with different masses are fabricated to match different propellant powder charges, then the firearm can accommodate different ammunition types, but the manufacturing complexity and cost increase
Solution Approach 1:
The bolt is divided into two separate pieces: a rear bolt piece that defines the breech face and remains fixed, and a front bolt piece that can be interchanged. This segmentation allows the front piece to be optimized for mass matching different powder charges while the rear piece maintains consistent breech geometry, thereby accommodating different ammunition types without increasing overall bolt design complexity
Solution Approach 2:
The rear bolt piece is designed as a universal component that can work with multiple front bolt pieces of different masses. This multi-functionality allows a single rear bolt piece design to serve multiple ammunition types, reducing the total number of unique bolt variants needed while maintaining adaptability
2Adaptability or versatility
If a complete bolt is purchased when changing caliber, then the firearm can be adapted to new calibers, but the cost increases significantly
Solution Approach 1:
By segmenting the bolt into replaceable front and rear pieces, the system allows users to change only the front bolt piece when changing caliber or powder charge type, rather than replacing the entire bolt. This reduces material loss and cost while maintaining full caliber adaptability
Solution Approach 2:
The design enables selective replacement of only the necessary component (front bolt piece) when adapting to different calibers, allowing the more expensive rear bolt piece to be recovered and reused. This minimizes waste and reduces the economic burden of caliber changes
3Adaptability or versatility
If the bolt mass is increased to match higher powder charges, then the bolt can handle more powerful ammunition, but the bolt becomes heavier and may affect firearm balance
Solution Approach 1:
The bolt system becomes dynamic in mass configuration, allowing the front bolt piece mass to be changed based on the specific ammunition being used. Users can select lighter front pieces for lower powder charges and heavier front pieces for higher powder charges, optimizing performance without permanently increasing the baseline bolt weight
Solution Approach 2:
The mass parameter of the bolt assembly is made variable through interchangeable front pieces with different masses. This allows precise matching to different powder charge levels while maintaining the ability to adjust the mass parameter as needed, rather than being locked into a single fixed mass
Data Source
AI summary
A modular two-piece bolt system for firearms with blowback actions provides a rear bolt piece which detachably couples to plural different front bolt pieces each of different mass. The front bolt pieces have a similar configuration and common coupling interface which forms an interlocked relationship with a complementary configured coupling interface on the rear bolt piece to prevent axial separation of the pieces when the action of the firearm is cycled. The system allows various front bolt pieces to be selected and used interchangeably with the rear bolt piece so that a front bolt piece of proper mass can be matched to the energy of ammunition to be fired. The front and rear bolt pieces when coupled define a continuous extended longitudinal passage which receives the rear breech end portion of the firearm barrel therethrough to reduce the projected length of the barrel.