Rifled-Bore Projectile Cartridge With Frangible Cap Patterning
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Solution Overview
Problem
Precision grenadier systems struggle to effectively engage close combat targets within a range of less than about 75 meters, despite advancements in ammunition technology for longer ranges.
Innovation Solution
Development of ammunition cartridges configured to deliver projectiles with selected size, velocity, and pattern distribution, suitable for engagement of close combat targets, featuring a robust design for semi-automatic operation in rifled barrels, and incorporating features like obturating rings, driving bands, and frangible caps to control spin and separation for predictable patterning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ammunition is optimized for long-range engagement (up to 1,000 meters), then range and accuracy are improved, but effectiveness against close combat targets (less than 75 meters) deteriorates
Solution Approach 1:
The projectile is segmented into a body and a frangible cap that separates during flight. The frangible cap contains additional fragmentation elements that deploy after separation, creating two distinct functional phases: initial stable flight and subsequent fragmentation pattern expansion. This segmentation allows the same ammunition to effectively engage both distant and close targets.
Solution Approach 2:
The ammunition system transitions from a static configuration to a dynamic one through the frangible cap separation mechanism. The cap is designed to remain attached during long-range transit for stability, then dynamically separate and fragment at closer ranges to create lethal patterns. This dynamic transformation enables adaptability across different engagement distances.
2Length of moving object
If a short rifled barrel is used (less than 18 inches), then system portability and length are improved, but propellant pressure control and projectile delivery reliability worsen
Solution Approach 1:
An obturating ring is introduced as an intermediary component between the propellant charge and the barrel bore. This ring seals the propellant gases, ensuring complete combustion and consistent pressure generation even in the short barrel environment. The driving band acts as another intermediary to reliably engage the rifling and transfer propulsion forces to the projectile, compensating for the reduced barrel length.
Solution Approach 2:
The system utilizes parameter changes in propellant pressure and projectile velocity to optimize performance in the short barrel. By carefully selecting propellant types and quantities, and adjusting projectile mass and aerodynamic properties, the system achieves reliable delivery despite the constrained barrel length.
3Speed
If high propellant pressure is used (30,000 psi), then projectile velocity and range are improved, but control over spin rate and patterning precision worsens
Solution Approach 1:
The projectile is divided into a body and a frangible cap that separates during flight. This segmentation allows the body to maintain stable flight characteristics at high velocities, while the frangible cap creates controlled fragmentation patterns after separation. The high spin rate from the short barrel is tolerated because the fragmentation pattern is determined by the cap's design rather than spin-induced dispersion.
Solution Approach 2:
The frangible cap is designed with predetermined fragmentation characteristics that replicate a desired pattern regardless of the high spin rate. By carefully engineering the cap's geometry, material properties, and attachment mechanism, a consistent lethal pattern is achieved that copies the intended distribution even under high-velocity conditions.
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 cartridges enable reliable engagement of close combat targets at ranges of at least 35 meters, providing predictable projectile patterning and lethality with controlled spin rates and separation, enhancing the capabilities of precision grenadier systems.
Implementation Method 1
a propellant charge disposed in at least a portion of the case cavity and configured to deliver the projectiles to a target
Implementation Method 2
Delivery of projectiles from a rifled bore
Data Source
AI summary
A 25 mm ammunition cartridge centered about a longitudinal axis and extending from a proximal end to a distal end including a case having a base defining the proximal end and a case sidewall extending from the base to a distal mouth and defining a case cavity, a propellant charge disposed in at least a portion of the case cavity, a body having a proximal cup and a body sidewall extending to a distal interface, wherein at least a proximal portion of the body is receivable in the case cavity distal to the propellant charge, a cap extending from a proximal cap portion coupled to the distal interface of the body to a dome defining the distal end of the cartridge, wherein the body and the cap define a projectile cavity, and one or more projectiles positioned within the projectile cavity.