Bullpup Rifle Fire Control Sear Mechanism
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Solution Overview
Problem
The bullpup firearm configuration poses a challenge for developing well-controlled fire control mechanisms due to the spatial separation of the trigger from the bolt and intervening magazine and cartridge path, which complicates the engagement and control of the firing pin.
Innovation Solution
A fire control system where the trigger located forward of the bolt engages the firing pin at its forward end, utilizing a sear that extends laterally from the bolt, with a sear stop pin controlled by the trigger to minimize spatial separation and allow the bolt to move over a magazine without interference, enabling precise firing operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the fire control system engages the firing pin at a point behind the magazine (conventional configuration), then the magazine positioning is convenient and practical, but the spatial separation between trigger and bolt increases, complicating the fire control mechanism in bullpup designs
Solution Approach 1:
The sear extends laterally from the bolt (perpendicular to the bolt's longitudinal axis) to engage the firing pin at the forward end. This dimensional change in sear orientation allows the trigger to control the firing pin despite the spatial separation inherent in bullpup configurations, resolving the contradiction between magazine positioning convenience and fire control mechanism complexity
2Ease of operation
If the sear is located directly below the bolt longitudinal centerline (conventional position), then the firing pin control is direct, but the sear contacts or interferes with cartridges in the magazine during bolt movement
Solution Approach 1:
The sear is positioned asymmetrically, extending laterally from the bolt at a location separated from the bolt longitudinal centerline. This asymmetric positioning allows the bolt to move forward and backward over the magazine without the sear contacting cartridges, while still maintaining effective control of the firing pin through the lateral extension
3Length of moving object
If the trigger is located behind the barrel opening (conventional position), then the overall firearm length can be reduced, but the spatial separation between trigger and firing pin increases, preventing well-controlled fire control mechanisms
Solution Approach 1:
The fire control system is segmented into distinct functional components: the trigger mechanism, the sear extending laterally from the bolt, the sear stop pin in the barrel, and the firing pin. This segmentation allows each component to be optimally positioned for its function, enabling the trigger to be located forward of the barrel opening while maintaining precise control over the firing pin through the lateral sear extension
Data Source
AI summary
A novel fire control system for a bolt action firearm includes a firing pin sear located and controlled at one side of the forward end of the bolt. The sear configuration is optimum for rifles having a bullpup form. The location of the sear also provides clearance under the bolt for the bolt to be moved over a firearm magazine without interference with cartridges in the magazine.