AR15 Bolt Carrier with Integral Key and Angled Strike Face
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Solution Overview
Problem
The AR15/M16 series of firearms suffer from carrier tilt during operation, malfunctions due to dirt and sand, and inability to function in aquatic environments, necessitating improvements in bolt carrier design to address these issues.
Innovation Solution
A bolt carrier with an integrally formed carrier key having a spherical strike face and cylindrical counterbore to prevent carrier tilt, an enlarged boss with water-passing flutes, extended rails for improved support, and drain holes to facilitate operation in adverse conditions, along with a super alloy operating rod for enhanced durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a separate carrier key attached to the carrier with fasteners is used, then the carrier can be cycled in automatic and semi-automatic operation, but the manufacturing precision requirement increases due to the need for close fit within narrow tolerance
Solution Approach 1:
The carrier key is integrally formed as one piece with the carrier body, eliminating the separate attachment step. This integration removes the fastening interface and ensures a permanent, precise fit without requiring additional manufacturing precision for assembly, while maintaining the carrier cycling function
2Ease of operation
If the strike face is positioned above the central axis of the bolt carrier, then the operating rod can contact the strike face during firing, but carrier tilt occurs causing the rear of the carrier to tilt downwardly and resist rearward movement
Solution Approach 1:
The strike face is designed with a specific angular orientation relative to the carrier axis, creating an asymmetric contact geometry. This asymmetric design allows the operating rod to contact the strike face effectively during firing while the angled surface redirects forces to prevent carrier tilt, maintaining carrier alignment stability
Solution Approach 2:
The strike face angle parameter is optimized to change the force vector direction during operation. By adjusting this geometric parameter, the design achieves both effective firing contact and carrier tilt prevention, resolving the contradiction between operational capability and alignment stability
3Stability of the object's composition
If conventional contiguous rails are used on the bolt carrier, then the carrier is supported within the receiver, but the firearm becomes prone to stoppages and malfunctions when sand or dirt works into the receiver
Solution Approach 1:
The rail surface is segmented with transverse grooves or discontinuities that create separation zones. This segmentation prevents continuous contact between the rail and receiver, allowing sand and dirt to be excluded from the contact interface while maintaining carrier support stability through the segmented rail structure
4Stability of the object's composition
If the rear of the carrier is supported by longitudinal rails rather than contacting the receiver, then the carrier can be supported against carrier tilt, but the carrier cannot immediately function after exposure to water in aquatic environments
Solution Approach 1:
Water is extracted from the receiver extension through drain holes positioned at the rear and bottom. This extraction mechanism removes water that would otherwise interfere with carrier operation, enabling immediate function after aquatic exposure while maintaining carrier tilt resistance through the longitudinal rail support structure
Data Source
AI summary
A bolt carrier for use with the AR15/M16 family of firearms is provided. The bolt carrier includes an integrally formed carrier key and spherical strike face surrounded by a cylindrical counterbore made with a downward angle to act against the tilting force imparted by the operating rod of the firearm's gas operating system. The outer surface of the carrier includes upper and lower running rails that all extend fully to the front face of the carrier to lengthen the carrier's rail support or bearing surfaces against the receiver. To improve the robust operation of the firearm in over the beach operations, the bottom and rear of the receiver extension has drain holes formed through which water is forced out of the receiver extension by the reciprocating action of the bolt carrier when the weapon is fired.