EFFICIENT MUZZLE BREAK DESIGN
CST is honored to have the opportunity to work with Superior Shooting Systems developing a new muzzle brake to compliment and enhance the new Tubb Adaptive Target Rifle. With so many different offerings currently on the market, to design something innovative and effective is no small feat. The culmination of ideas has led to a brake that not only offers simplicity of construction, but highly efficient functionality as well.
Designed specifically to better maintain target acquisition after the shot to detect bullet impacts and allow faster follow-ups, the new Tubb Five-Star Muzzle Brake has become standard equipment for the new Tubb Adaptive Target Rifle.
Regardless of the platform used, where a high performance muzzle brake is required with so many available, testing has proven the Tubb Five-Star Muzzle Break absolutely invaluable.
Now available at davidtubb.com.
For more technical details and the background behind developing the new muzzle brake, (and for those who like to read), check out below the pics our: “Essay: Efficient Gas Diverging Muzzle Brake”
Linear Cross-Section displaying width of expansion chambers created by intersection of port holes. Unique design creates large surface areas while minimizing weight.
Partial sectional displays middle/right cutting edge of first expansion chamber. Designed to "shave" expanding gas into radial surface of the ports for maximum efficiency redirecting gas.
Essay: Efficient Gas Diverging Muzzle Brake
When tasked with developing a muzzle brake that would compliment and enhance the shooting system of the new Tubb Adaptive Target Rifle, CST considered the vast array of designs already available. The fundamental principle is to redirect expanding gas from its forward path to not only reduce felt recoil, but more importantly to prevent the disruption of the rifle and sight picture. The latter point will both allow the detection of bullet impact seen though the scope as well as allow a faster follow-up if needed. In this regard, the larger the caliber and the shorter the time-of-flight, the better the brake needs to be.
Brake designs can range from simple through holes with multiple perpendicular drilled ports to more elaborate brakes with expansion chambers and back angled ports. While there are an endless amount of configurations of muzzle brakes currently available, for the purpose of developing a new brake, CST considered pros and cons of these two basic designs.
Perpendicular Ported Brakes:
Perpendicular ports, whether they are simple drilled holes or more arbitrary shaped, are relatively less complex and simple to manufacture. The ports will redirect the maximum amount of gas when the bullet’s base just passes the intersection of the port and is still blocking the forward movement of gas. For this reason, a minimal amount of clearance between the bullet’s diameter and the through hole in the brake is very beneficial, creating a better seal with the bullet and thereby forcing more gas through the ports instead of allowing the gas to continue forward.
As the bullet continues forward, this back pressure drops and will drop dramatically once the bullet exits the brake into open air. While the intense pressure of the expanding gas will continue to force itself to exit through the ports, efficiency will seemingly drop rapidly once the bullet has left the brake. Peak efficiency would therefore occur during the very brief time the bullet is passing through the brake. For this reason, utilizing many ports along the circumference of the brake will be beneficial, allowing more gas under back pressure to be diverted.
For the pro of simplicity, we have some cons. A close fitting through-hole requires special care in alignment of the brake to the barrel to prevent bullet strikes inside the brake. Even with this correct, we still have rapid loss of efficiency once the bullet leaves the brake. With brakes that have ports all along its circumference, we have another con of gas exiting the bottom ports blowing up dust and debris, exasperated by shooting close to the ground in prone position. Stirring up dirt can prove a deterrent to detecting impacts and follow up shots and in a tactical situation the dust signature can cause loss of concealment.
Expansion Chambers / Back-Angled Brakes:
While brakes using expansion chambers will benefit from back pressure created by the bullet passing through the brake, by design the gas is allowed to expand, traveling forward and laterally to be collected and redirected. This allows gas as it continues to expand to be better collected and diverted even after the bullet has left the brake. Its design of allowing gas to expand permits high volumes of gas to be diverted completely to the sides and not downward unto the ground.
Another predominate design feature is creating expansion chambers with an initial forward angle discontinued by a dramatic rear angle, the latter angle the final path created for diverted gas. The concept is to cause the forward moving gas to suddenly hit a capturing cavity, using the forward energy of the gas to counter rear moving energy (recoil).
While brakes using expansion chambers and back angled ports are widely considered the most effective, there are some cons to consider. Not only are the back angles more complex and difficult to manufacture, they have an undesirable feature of creating an extra amount of “back-splash” of gas (and noise) towards the shooter and especially a spotter or anyone to the side of the shooter.
The speed of the expanding gas is to be considered as well, (about twice that of the bullet). Attempting to capitalize on the forward energy of gas by creating capturing cavities can in effect create blockages of gas. The path of least resistance for the expanding gas, particularly after the bullet has exited the brake, would then be the least desirable by traveling forward out the muzzle.
After considering the pros and cons of the two designs described above, CST decided on a simple concept: the brake that redirects the most volume of gas wins. More specifically, the most gas that can be prevented from taking a forward path is the overall goal. Given the very short period of time available (milliseconds) and the sheer violence of rapidly expanding gas during discharge, creating geometry to more efficiently collect and redirect the gas was needed.
In any design muzzle brake it was decided the biggest challenge was to collect gas after the bullet has exited the brake. CST theorized that expansion chamber type brakes will have more of an advantage over simple ported brakes as higher velocity and powder volumes are used. The bullet doesn’t stay inside a simple ported break long enough to best redirect all that gas, and without expansion chambers to collect gas after the bullet has exited, a good deal of that high velocity gas simply travels out the muzzle. As a key improvement, to allow these expansion chambers to be most effective, it was decided to clear them of gas as quickly and efficiently as possible to allow even more gas to be collected. If this occurs after the bullet has exited the brake, it would be that much more pronounced during passage through the brake.
Geometry needed to be created that not only redirected gas from its forward path, but as the more pressure of gas encountered it, the more it would push itself clear, thereby using the intense pressure to allow the collection of even more gas. While peak pressure will always occur during the passage of the bullet through the brake, (as with any muzzle brake), geometry needed to be created to continue the efficient collection and redirection of gas after the bullet has exited.
Solution:
In the end, expansion chambers were used but CST opted to use perpendicular ports in the shape of simple holes to create them. While perpendicular ports prevents “back-splash” of gas and noise, it was really a matter of simple mathematics. An angle more than 90 degrees would not as efficiently clear gas, and while an angle less than 90 degrees would, there would still be forward movement of gas. The minimum angle to deviate the gas from an undesirable forward path was 90 degrees from the barrel’s bore.
To create expansion chambers with perpendicular holes, four holes were machined at an angle offset from center. As the holes intersected, an elliptical cavity was created inside the brake with sharp edges all along the perimeter. As opposed to impacting an immediate square surface or a capturing cavity, when the expanding gas enters these expansion chambers it is simply rolled along the radius of the holes, effectively “shaved off” by the sharp edges along the perimeter, providing a highly efficient means to redirect and force the gas to disperse out the perpendicular ports. This process will repeat for the gas that enters subsequent chambers along the length of the brake. After the bullet has cleared the brake, the sharp scallop edges of the expansion chambers will continue to function much like “hooks”, scaling off expanding gas diverting it out the ports.
A practical advantage of this design is ease of manufacture, (no five-axis machining, compound angles required, etc.). Per design parameters requested, to accommodate asymmetrical exiting of gas to counter barrel rise and rifling-twist torque, top holes and extra relief cuts along the outside of the ports have been added respectively. Importantly however, the surfaces along the through-hole are symmetrical allowing the enlargement of the through-hole for specific calibers with simple drills. Finally, the unique design allows a large amount of surface area available in the expansion chambers while creating minimal weight to the overall component.