Firearm Barrel Grooved Gas-Venting Pattern Reduces Bullet Velocity
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Solution Overview
Problem
Existing firearm barrel designs that reduce bullet launch velocity to subsonic levels are cumbersome, increase the physical envelope and mass of the weapon, and require complex maintenance due to the need for gas venting features that increase the barrel's complexity.
Innovation Solution
A firearm barrel with a grooved rifling pattern and a grooved gas-venting pattern that exceeds the envelope of the rifling pattern, allowing propellant gases to escape around the bullet and reduce internal pressure, thereby reducing bullet velocity to subsonic levels without the need for specialized ammunition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If gas venting features (holes or slots) are implemented orthogonally to the bore leading to an enclosed outer expansion volume, then bullet launch velocity is reduced to subsonic levels, but the physical envelope, mass, and center of gravity of the weapon are increased
Solution Approach 1:
The gas venting grooves are implemented longitudinally along the bore axis rather than orthogonally to it, changing the dimensional orientation of the gas venting features. This allows gas to escape in the longitudinal direction through grooves that extend along the bore, eliminating the need for an enclosed outer expansion volume and associated barrel jacket, thereby reducing overall weapon mass while maintaining subsonic velocity capability
2Speed
If gas venting features are implemented orthogonally to the bore with an enclosed outer expansion volume, then bullet launch velocity is reduced to subsonic levels, but the barrel system becomes more complex and requires partial disassembly for cleaning
Solution Approach 1:
The gas venting grooves are merged with the existing rifling grooves, combining the gas venting function with the existing barrel structure. The grooves are configured to receive both the bullet and propellant gases, eliminating the need for separate gas venting ports and associated barrel jacket components, thereby simplifying the overall barrel system and maintaining ease of cleaning
3Object-affected harmful factors
If specialized subsonic ammunition is used, then sound signature is reduced, but logistical and supply challenges arise and acquisition may be delayed
Solution Approach 1:
The barrel is modified by adding grooved gas-venting features that change the pressure parameters of the propellant gases during combustion. This parameter modification allows standard supersonic ammunition to function as subsonic ammunition when fired from the modified barrel, eliminating the need to acquire specialized subsonic ammo and enabling immediate use of existing standard ammunition supplies
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 solution effectively reduces bullet velocity to subsonic levels, eliminating the loud crack of a gunshot and allowing for maximum audible signature reduction, while maintaining the stability and accuracy provided by the rifling pattern, and does so without increasing the weapon's complexity or maintenance requirements.
Implementation Method 1
The grooved gas-venting pattern allows expanding propellant gases to escape around the bullet as it travels down the bore, causing a reduction in internal pressure acting on the bullet and reducing bullet velocity
Implementation Method 2
The grooved rifling pattern imparts spin on a bullet to stabilize the bullet in flight
Data Source
AI summary
Disclosed is a firearm barrel that includes a bore, a rifling pattern along a length of the bore, and a grooved gas-venting pattern along a length of the bore that exceeds an envelope of the rifling pattern. The rifling pattern imparts spin on a bullet to stabilize the bullet in flight, while the grooved gas-venting pattern allows expanding propellant gases to escape around the bullet as it travels down the bore, causing a reduction in internal pressure acting on the bullet and reducing bullet velocity. The inventive barrel can reduce bullet velocity of standard ammunition, such as 5.56×45 mm NATO or 7.62×51 mm NATO to a subsonic velocity, or approximately 1125 feet per second at sea level without the need for specialized ammunition.