Two-Part Expanding Bullet Core for Controlled Fragmentation
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Solution Overview
Problem
Existing deformation and partial fragmentation projectiles, particularly those without lead, suffer from inconsistent fragmentation and detachment of the core from the jacket upon impact, leading to reduced performance and reliability.
Innovation Solution
A two-part core design is implemented, where the rear core section is more strongly attached to the jacket than the nose core section, using different connection techniques such as soldering and frictional locking, ensuring reliable deformation and fragmentation upon impact, with the rear core remaining attached and the nose core detaching as needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the core is pressed into the bullet jacket, then the manufacturing process is simple, but the bond between jacket and core is not durable and strong
Solution Approach 1:
The core is divided into two distinct parts: a rear core section that is strongly bonded to the jacket and a nose core section that is less strongly attached. This segmentation allows each section to serve different functions - the rear section provides reliable attachment while the nose section enables controlled detachment and fragmentation upon impact.
Solution Approach 2:
Different attachment strengths are applied to different parts of the core. The rear core section has strong bonding (through soldering, diffusion bonding, or mechanical interlocking) while the nose core section has weaker attachment (through pressing or frictional locking). This local differentiation in bond quality enables the desired performance characteristics.
2Object-affected harmful factors
If lead-free materials are used for the core, then the bullet is environmentally friendly, but the core fractures upon impact without leaving a deformed fragment
Solution Approach 1:
The bullet employs composite material construction with a lead-free core (tin, zinc, or their alloys) combined with a copper or copper alloy jacket. The core materials are selected for their environmental benefits and non-toxic properties, while the harder jacket provides structural integrity and controlled deformation characteristics.
Solution Approach 2:
The patent modifies the physical and mechanical parameters of lead-free materials through alloying (combining tin and zinc in specific proportions) and controlled deformation design. The core is designed with specific geometric features and attachment characteristics that enable it to deform controllably rather than simply fracture, achieving reliable fragmentation performance.
3Strength
If the core is strongly attached to the jacket, then the structural integrity is high, but the core does not detach upon impact for controlled fragmentation
Solution Approach 1:
The core is segmented into two parts with different attachment characteristics. The rear core section is strongly attached to maintain structural integrity during flight, while the nose core section is less strongly attached to enable controlled detachment and fragmentation upon target impact.
Solution Approach 2:
The attachment system is designed to be dynamic rather than static. The bonding strength varies along the core length and can change under different stress conditions. The rear section maintains strong bonding under normal conditions while the nose section allows for controlled detachment when impact forces are applied.
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
This design ensures a defined residual fragment is left upon impact, enhancing energy transfer and reliability, while eliminating the need for additional structural measures like retaining grooves, thus simplifying manufacturing and reducing costs.
Implementation Method 1
The core section at the rear of the projectile is soldered to the adjacent jacket
Implementation Method 2
The core section at the nose of the projectile is frictionally locked, in particular pressed, in the jacket
Data Source
Figure 1~2
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AI summary
The invention relates to an expanding and/or partially fragmenting bullet (1) comprising a jacket (3) and a two-part core arranged inside the jacket and having a bullet-point core part (31) and a bullet-base core part (9), the core being attached to the jacket such that the bullet-base core part is attached more firmly to the jacket than the bullet-point core part.