Annular Narrow Bullet Design for Friction and Pressure Control
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Solution Overview
Problem
Long range bullets experience excessive in-barrel friction and pressure buildup due to the requirement for a good seal and rifling engagement, leading to potential catastrophic explosions and reduced aerodynamic performance from traditional groove designs, which increase drag and lower ballistic coefficients.
Innovation Solution
A bullet design featuring one or more annular narrows on the bearing surface, with a combined length of at least one-third of the bearing surface and depths between 0.005 mm to half of the barrel groove depth, providing controlled friction and gas sealing while maintaining aerodynamic performance by reducing material contact and promoting concentricity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If traditional grooves are used on the bearing surface to control in-barrel friction and pressure, then chamber pressure is controlled and rifling engagement is improved, but aerodynamic drag increases and ballistic coefficient decreases
Solution Approach 1:
The bearing surface is segmented into multiple discrete annular narrows rather than continuous grooves. This segmentation reduces the total contact area with the barrel while maintaining pressure control at critical locations, thereby reducing aerodynamic drag during free flight while still controlling chamber pressure during firing.
Solution Approach 2:
The narrows are strategically positioned at specific locations on the bearing surface where pressure control is most needed, rather than using continuous grooves around the entire circumference. This localized approach maintains gas sealing and pressure control where required while minimizing aerodynamic penalty during flight.
2Reliability
If a good seal between bullet and barrel bore is required for accurate shooting, then rifling engagement is improved, but in-barrel friction increases causing high chamber pressures
Solution Approach 1:
The seal is achieved through multiple discrete annular narrows that create localized sealing zones, rather than relying on continuous contact. This segmented sealing approach maintains adequate gas seal for reliability while reducing overall friction and chamber pressure compared to continuous bearing surfaces.
Solution Approach 2:
Instead of providing full continuous contact for sealing, the invention uses partial contact through discrete narrows that provide sufficient sealing action at critical locations without the excessive friction of complete surface contact throughout the bearing area.
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
The annular narrow design reduces friction and pressure buildup, maintaining optimal aerodynamic properties and preventing over-pressure issues, allowing for increased muzzle velocity and stable flight with minimal impact on ballistic coefficients.
Implementation Method 1
The inventor is aware of, from an internal ballistics point of view, the requirement for a good seal between the bullet and the bore of the barrel and engagement with the rifling of the barrel. However, this requirement causes friction and drag in the barrel as the bullet accelerates through the bore of the barrel
Implementation Method 2
The chamber pressure is at its peak shortly after ignition of the propellant. If the peak pressure is too high, it can cause a catastrophic explosion
Implementation Method 3
It can be shown that the typical drag of a groove will be significantly decreased by adjusting the leading and trailing edge angles of the groove to create weak shock waves instead of strong shock waves during supersonic flight
Data Source
AI summary
The invention provides a long range bullet. The bearing surface of the body of the bullet is provided with one or more annular narrows of which the combined length is at least one third of the length of the bearing surface of the bullet and which depth is between 0.005 mm up to half of the groove depth of a barrel in which the bullet is intended to shoot.