TACOM HQ®
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“Incoming fire has the right of way." - Unknown
Structured Barrel
INSIGHTS
TACOM HQ is the leader in innovative, firearm accessories, and renowned for its cutting-edge products designated to enhance the modern warfighter. We are the proud creators of the Structured Barrel, a revolutionary, patented design so end users can shoot longer, run cooler, and mitigate recoil for quick, follow-up shots. Comprising internal and external geometries machined from a monolithic barrel blank, no other industry solution matches our rate for cooling and stiffness to maintain barrel stability in prolonged engagements. Structuring adds a massive +300% surface area and +50% more rigidity compared to a barrel of the same weight, so Structured Barrels demonstrate superior endurance in combat or competition. We add stability for reliability.
At TACOM HQ, we idealize physics, rooting our research and application in engineering discipline. It is for this reason a Structured Barrel is one of the most highly sought after high performance barrels for sale in the industry, because its I-beam geometry generates +300% more surface for cooling, rapidly evacuating heat out of the system instead of relying on materials with different thermal expansion coefficients or mass to compensate. Unlike any other barrel, this makes the chamber of a Structured Barrel uniquely the coolest section. The added heat dissipation also and distinctively preserves material stiffness as this property is temperature dependent. Since metal becomes more malleable with heat, Structured Barrels with its high surface-area-to-volume ratio exude greater endurance and overall life.
The I-beam geometry also serves to overcome flexion. Boasting +50% more rigidity than a barrel of the same weight, Structured Barrel’s large diameter, I-Beam, and other structural elements impart far greater resistance to forces generated by gas pressure, recoil, and bullet-barrel interaction. These forces work to simultaneously push, pull, stretch, compress, and twist the barrel in multiple planes, relaying the speed and magnitude each displacement as a frequency and perceived as barrel whip, and they generate a lot of heat through material friction. The added rigidity ensures a more stable platform throughout recoil, mitigating thermal rise, and increases the accuracy of rapid, follow-up shots.
Flexion is a byproduct of an object’s material stiffness, structural stiffness, and mass distribution. While adding a brake or suppressor alters mass distribution, changes in barrel length or diameter affect structural stiffness, and material stiffness encompasses metallurgy, like 416SS or chromoly, each affecting the barrel at varying degrees, heat fundamentally drives the system. Heat changes both material stiffness and structural stiffness via thermal expansion, altering mass distribution, and this causes systemic barrel degradation, making them anything but constant.
The combination of 300% more surface area and 50% rigidity work in concert to ensure Structured Barrels remain stable, every feature is purposely designed to optimize structural and thermal performance. Whether in the field or at the range, Structured Barrels enable end users to engage targets through prolonged shot strings without compromise or concern for mirage obscuring the target. This makes them a preferred choice for any serious shooter.
When choosing TACOM HQ, you’re not just purchasing innovative, cutting-edge gear; you’re gaining access to an entire team committed to your success. Whether you’re a military combatant, law enforcement officer, professional shooter, or an 2A enthusiast, TACOM HQ offers the next level in barrel technology for sustained performance. Contact us today to learn more about our product and how we can assist to unlock next-level efficiency.
How Structured Barrels Work
The following offers various physical and mathematical proofs and FEA (Finite Element Analysis) models and simulations using MSC/NASTRAN and LS-DYNA to describe Structured Barrels; independently peer-reviewed by a team of aeronautical engineers.
1.1 Axial Stiffness
Structural stiffness is a measure of an object’s resistance to deflection when subjected to a force. Axial stiffness is one example that refers to a structure’s resistance to deformation along its longitudinal axis when a parallel force is applied. It is quantified by a coefficient that represents the relationship between an axial force (F) and the resulting axial displacement (x). A basic example, in finite terms, is an axial spring where deflection is defined as F = kx, also known as Hooke’s Law, where F is the applied force, k is the spring coefficient / stiffness constant, and x is the displacement. The following image demonstrates as load increases, deflection increases. Less visually obvious, though, is as spring stiffness increases, deflection decreases. In a rifle barrel, axial stiffness is a linear function of the cross-sectional area and its material stiffness (modulus of elasticity).
Axial stiffness in structural engineering analyses account for structural weight, external force(s), and in mechanical systems, like shafts and columns, determines the structure’s ability to maintain alignment and resist deflection when subjected to an axial load. Axial stiffness also includes vibration as this affects how an object elongates and contracts under load.
1.2 Bending Stiffness
Unlike axial stiffness, bending stiffness is the measure of an object’s resistance to deflection when subjected to a lateral load, or an end bending moment, and by increasing material distribution in the plane of the force will yield greater resistance to flexion. This concept is simplified by evaluating the below figure. Click here for a complete video animation.
Flexion caused by a bending load may be calculated using closed form equations from simple cross-sections, but for variable section beams, like Structured Barrels, a more complex method like finite elements is required. In general, though, bending stiffness is linearly related to the moment of inertia of the cross-sectional area. Therefore, comparing the relative bend resistance of two objects (conventional barrels versus a Structured Barrel) is done by contrasting their respective moments of inertia and as a function of section area.
1.3 Natural Frequency
An object’s resistance to bend is intrinsic to its mass distribution, structural stiffness, and material stiffness (modulus of elasticity). Tuners, like suppressors, can alter mass distribution, changes in length and diameter affect structural stiffness, while 416SS, 400 MOD, or chromoly exhibit different material stiffnesses. Each yields varying degrees of influence depending on the scale of the variable change and its relationship to the system’s overall mode.
These three functions drive an object’s natural frequency and its resistance to deflection. This can be clearly understood by considering the sound an object makes when struck. The pitch of that sound is the audible frequency at which the object is bending to some displacement value in oscillation. For example, when a tuning fork undergoes resonance, it vibrates at some frequency until energy dissipates through grounding and friction.
Similarly, barrels want to vibrate at their natural frequency(s) during a firing sequence, but in the case of rifles, it is not just barrel stiffness that determines its behavior. The attachment to the stock/chassis, the stiffness of the bipod/mount, the stiffness of the bipod interface with the ground, and the stiffness of the rifle interface with the shooter all serve as a unique interfaces comparable to a spring with its own stiffness constant, and since they are all attached to the same body, they all simultaneously affect the system’s dynamics. It is important to note, wave functions propagate ideally through uniform, homogeneous mediums, and those that diverge from the natural frequency of a body or individual component generate irregularities and non-repeating wave patterns that induce amplitudes perceived as vibration, which dissipates by grounding and friction.
1.4 P and S Waves
Vibration consists of S and P waves. S waves are sinusoidal functions while P waves are complex sheering functions generated from compressive and expansive forces. When a barrel undergoes flexion, S and P waves resonate at 8,000 and 13,000 mph, respectively, traversing the barrel’s entire length many times before the bullet even exits the muzzle. Examples of a S and P waves include barrel whip and the compression of the barrel acted by bullets engaging rifling and high bore pressure, respectively.
1.5 Temperature and Waves
The speed with which these waves travel through the barrel though varies by temperature. Greater the temperature yields greater atomic vibration, and this increases the distance between atoms and thus the time for one atom to collide with another atom to relay a wave at some frequency. Since all atoms vibrate, a consequence of having a temperature above absolute zero, temperature drives the five material states: solid, liquid, gas, plasma, and Bose-Einstein condensate. Wave functions travel more efficiently through solids than liquids and in liquids than gases (with minimal energy loss in the vibration of the atom itself) due to atomic vibration and atomic arrangement density. In other words, atoms are more closely packed in a solid and so on. Waves are described by the equation λf = v. Click on the following video animations on Sound Waves and Sound Propagation in Different Mediums.
1.6 Barrel Flexion and Waves
As heat flows from a high to low energy state, from low to high entropy, incremental increases in temperature induce infinitesimally small changes in the efficiency of the medium to conduct waves as the medium itself undergoes infinitesimally small phase shifts from solid to liquid. Sinusoidal S and compressive P waves are generated by gas pressure, recoil, and the interaction between the bullet and the barrel in way of rifling, bore concentricity and straightness, and gravitational torque imparted on the barrel itself. These waves are the derivative of immense forces working to simultaneously push, pull, stretch, compress, and twist a barrel. The speed and magnitude of each flexion is relayed as a frequency of displacement, and they respond to temperature gradients. Since these waves travel many times faster than the bullet, they create amplitudes that can further exaggerate the bullet’s interaction and effect(s) on the barrel, causing even greater deflection and accelerations about its center axis that is perceptible as barrel whip (a consequence of highly dynamic constructive and destructive interference patterns).
1.7 Ladder Tests
Conventional barrels exude sufficient stiffness, but since no object is absolutely rigid, flexion affects axial or lateral bend amplitudes, causing different shot patterns. Applying a Gaussian distribution, 67% and 95% of groups will fall within a 1 and 2 standard deviation, respectively. Bell curves like this are common to predict the likelihood of specific outcomes in various scientific disciplines. In other words, a rifle that yields a 0.5-moa group will do so most of the time. In theory, ladder tests should produce purely vertical groups with points of impact increasing in relation to increases in velocity if all other variables are kept constant. However, ladder tests almost always yield horizontal dispersion.
Given rifling only marginally affects BC (1-2% on a “shout-out” barrel) and hand loads further reduce error found in principal axis tilt or pressure curves, contrasts in group size and or position suggest other forces are at work. Shooters can compensate using their scope, zeroing to an observed position of precision. For example, if A-bullet shot an average (x,y) and B-bullet shot (x+1,y+1), technically, one could dial out the “+1” movement and make that zero, but this zero is now calibrated to those conditions, and changes in barrel temperature due to ambient air, sun soak, or long, shot strings introduce a variable. Thus, barrels that undergo horizontal dispersion from small variable change are likely reacting to one or more forces affecting flexion, which is exacerbated by heat as it changes material properties.
Focusing solely on the vertical plane, extremely small flexion values effect down-range results as depicted in the illustrations below. The image on the left is a 1.35″ DIA barrel. The image in the middle is the same barrel on the left, but magnified 8x. The light, thin gray line above the barrel represents 0.001″ of flexion. Therefore, measuring the DIA of the first image in real-life, and multiplying this value by 8x, totals the DIA of the barrel in the middle image to see the light, thin gray line above the barrel representing only 0.001″ of flexion. The image on the right depicts a barrel with varying degrees of flexion ranging from 0.0005″ to 0.002″ and its corresponding impacts at 100-yds on a scaled target. These calculations realize a 24″ barrel with a fulcrum 6″ from the chamber. This illustration further appreciates a nominal difference in trajectory arc for displaced ϴ ranging 0.0016° to 0.0064°. This is equivalent to 0.0954 MOA or 0.0278 MIL or 0.3822 MOA or 0.1112 MIL, respectively, which are discernible within a scope.
We see the difference between 0.0005″ and 0.001″ of flexion is only 0.100″, which is not only challenging to isolate among other variables, like CGI offset and or heat driving driving thermal expansion in consecutive 5-shot groups, but it would also be difficult to discern in a ladder test, giving rise to Gaussian distribution curves. So while the first order of dispersion may be visible movement, these small, near invisible movements about the barrel can have profound significance down-range. Again, this focuses solely on the vertical plane though for illustrative purposes, despite bullet-barrel interaction imposing flexion in multiple planes and affecting the magnitude of the offset, given their xyz vector components.
8x
1.8 Second Moment of Area
The S and P waves produced from gas pressure, recoil, and the bullet’s interaction with the barrel transfer enormous energy into the compression, tension, and torque of the barrel. As these linear and radial functions traverse the barrel, amplitudes manifest as acceleration and thereby a velocity about its center axis. This velocity is described by its moment of inertia while its flexion is described as its second moment of area.
To better visualize a barrel’s physical response to waves, the following models and simulations are accredited to Al Harral, in charge of performing engineering and structural analyses on complex systems for 30 years at Lawrence Livermore National Laboratory, a government R&D facility. Analyses utilized LS-DYNA Finite Element Code, a powerful program for analyzing the dynamic and static loading of structures. It is important to note, the following FEA simulations assume a perfectly straight bore and exhibit displacements that are greatly amplified so changes in shape can be easily perceived. The simulations exhibit “forced deformations from the high pressure gas and recoil cause the muzzle to change where it is pointing at the target when the bullet exits the muzzle (….) The recoil and bullet motions ‘pulls’ the rifle barrel to a new shape.” – Al Harral’s 3-D Finite Element Analysis of a Barrel’s First Few Vibration Mode Shapes and Frequencies. Hence, a barrel with superior stiffness will exhibit less flexion just from gas pressure and recoil alone. Further, the depicted simulations shows “The vertical amplitude of vibration is more heavily excited than the horizontal vibration, because the center of gravity of the rifle is located below the barrel’s center line and the bullet’s travel down the barrel causes a vertical turning moment about the rifles center of gravity. [Making] the vertical vibration most important” – Al Harral’s Barrel Tuner Vibration Analysis.
The simulated 6mm rifle assumes a 22″ 416 stainless barrel with no rifling and straight taper from 1.24″ at the breach to a 0.935″ DIA at the muzzle. The modeled barrel, action, stock, scope, scope mounts, brass weight, etc. came within approximately 7oz of the real thing. Mesh detail is provided, consisting of 17,196 nodes and 12,080 elements. Despite only half of the mesh being used in calculations, each shot calculation still took about an hour to set up and simulate, outputting about 2.5Gb of data.
Mode 1 – Cantilever Bending
82Hz
Mode 2 – 1 Node Bending
406Hz
Mode 3 – 2 Node Bending
1050Hz
Mode 4 – Axial Extension
1756Hz
Mode 5 – 3 Node Bending
1984Hz
The above simulations demonstrate how different frequencies manifest as physical movement along the barrel’s length. It is important to note, while modes 1, 2, and 3 are shown in a single plane, they may exist in other planes, and exemplary modes 1-5 are – all – excited, simultaneously when firing a round. While the higher frequency modes have extremely small amplitudes, it is difficult to visualize just five modes acting at the same time, let alone many more.
The amount of resistance a shape can exert to bending about its geometry on a particular axis is its second moment of area, and this is dependent on the area and material distribution to the axial moment. Cross-sections of an object that locate the majority of the material far from the bending axis have larger moments of inertia, making said cross section considerably more difficult to bend when force is applied. This is one reason I-beams, and not rectangular bars, are commonly used in structural applications, because they position sufficient mass in both x-y planes to resist force and deflection. Since Structural Barrels are analogous to I-beams reinforcing the bore in multiple planes, this creates a geometry that resists bending in multiple planes.
1.9 Mathematical Proofs for Increased Stiffness
Second Moment of Area (J) for a cross section of a barrel
J = ∫ r² dA; where r² = x² + y² and dA = 2π • r dr
J = ∫ r² • 2π • r dr = πR⁴/2
Perpendicular Axis Theorem Jz = Ix + Iy; barrels are a symmetric object
Ix = Iy = πR⁴/4
Second Moment of Area per Unit of Area | Rod (conventional barrel) versus Tube (Structured Barrel)
SRod = IRod / A; where A is the area πR² = R²/4
STube= (IRod / A) – (ITube / A) = R²(1+x²)/4
We see as the x limit approaches a 1:1 ratio to the radius R in the STube, a tube exhibits twice the stiffness, but this also requires an infinitely small radius. Nevertheless, these equations indisputably demonstrate a body of equal mass positioned farther from the bending axis has a larger moment of inertia, making it significantly more difficult to bend. This is further corroborated by an independent aeronautical CEL analysis that found +50% greater stiffness in a simulated barrel of the same weight.
Using R²/4, or the stiffness per unit area, we can evaluate this to a barrel that is X% larger, and the difference between a big and small barrel may be simplified as R²(1-X²)/4. Since X is the difference between two barrel diameters as a percent, it is important to note this value is driven by a square. So, procuring a 1.65″ blank versus a 1.35″ blank yields 22.50% more (free) stiffness. Compound this with added structural rigidity, and this value becomes rather significant. It is no secret bull barrels are typically more precise than a standard profile. Mathematically, this is one reason why.
2.1 Flexion and Energy
Gas pressure, recoil, and the interaction between the bullet and the barrel are all exemplary forces that act on a barrel The equation to describe force is the multiple of mass and acceleration, the rate velocity changes in respect to time. Since barrels have mass, the work done to accelerate a barrel onto a sinusoidal wave about its center axis via tensive and compressive forces requires energy. These relationships are described by the below equations:
v = x/t
a = dx/dt (rate of change)
F = m•a
W = F•Δx
ΔK = W
K = Energy (kinetic)
2.2 Energy and Temperature
Since energy is proportional to the work that acts on a system from an initial state to a final state (the First Law of Thermodynamics) and the Law for Conservation Energy dictates energy remains constant and is neither created nor destroyed, the work done on a barrel to accelerate it about its center axis due to flexion requires massive energy. Friction caused between atoms as the barrel accelerates into flexion generates heat, thereby raising barrel temperature and affecting material stiffness (modulus of elasticity). Even though each atom is not vibrating at the same rate, described by Maxwellian distribution, it is important to note the increase in thermal energy raises all individual atom vibrational speeds as an average, even though the medium as a whole will consist of multiple heat gradients along the barrel’s entire length.
2.3 Energy and Temperature
Bull barrels maintain a lower temperature than a standard profile, and a standard profile than a pencil barrel, a reason typically accredited to thermal mass. While this is correct, it fails to define the function and thereby other primary variables. Physics tells us the rate of heat transfer is directly proportional to the temperature difference and transfer area, but inversely proportional to the area’s thickness.
Q = kA • ΔT/ΔX; where k is the thermal conductivity coefficient
A = 2πrL (still L x W)
ΔX = Δr (for the radius)
In this evaluation, since temperature and radius are changing with respect to bore center, we use an integral ( ∫ ) to solve an infinite number of evaluations from r1 to r2. Rewriting and solving the above equation yields:
Q = 2πrkL • (T1 – T2) / Ln(r2/r1); (W)
This equation mathematically defines the amount of heat energy required to be conducted through the wall of a tube from bore r1 to bring the exterior r2 to temperature T2. If we increase wall thickness L by increasing r2 or temperature disparity ΔT, we see Q, the energy to reach temperature T2, also increases.
2.4 Thermal Expansion
The increase in vibration speeds affect the kinetic energy of individual atoms and thereby the properties of the material. In solids, atoms are closely packed together, held firmly by strong attractive forces. Since these atoms primarily vibrate about their fixed positions without moving past each other, solids have a definite shape and volume. These vibrations are described by Lennard-Jones Potential, a physics equation that evaluates the interaction and resulting potential energy between two atoms based on their distance of separation. Visualized as a spring linking two neighboring atoms, the potential energy is asymmetrical, increasing more steeply as two atoms get closer, a consequence of it taking more energy to compress two atoms together than to repel them apart, and this causes atoms to spend more time apart than together when oscillating. Thus, as the kinetic energy of atoms increases, the average distance between each atom also increases, thereby causing the material to expand. Since solids are isotropic, there is no preferred direction, so while proportions stay the same, the overall size changes by some fraction per degree (thermal expansion coefficient). This is called thermal expansion, or the tendency of matter to change in shape, volume, and area in response to changes in temperature.
Thermal expansion is defined by the physics equation:
ΔL = αL • ΔT
ΔL is the change in length
α is the thermal expansion coefficient
L is the starting length
ΔT is the change in temperature
Using 6.5 x 10-6 inches per °F as the thermal coefficient for 416 stainless steel, changes in ΔT will affect barrel length, diameter, and even bore diameter. Premiere bullet manufacturers segregate below a 0.0001″ margin of error, and simple air temperature, sun soak, or extended shot strings can easily accumulate +0.0001″ of bore movement. Using this equation assumes a uniform temperature about its entire longitudinal and radial length, so it is important to note temperature gradients realize different thermal expansion rates and material properties as layers undergo phase shifts.
2.5 Energy and Waves
As thermal energy increases, the barrel’s atomic arrangement density also decreases due to thermal expansion. This expansion is uniform per calorie, but not uniform about the barrel length due to many temperature gradients. Since the mass of the barrel remains unchanged but the overall distance between each atom increases, thermal expansion continuously changes the tendency for the barrel to conduct waves as the distance and associated time for one atom to collide with another atom to relay a frequency changes gradient to gradient. Section ‘Temperature and Waves’ aides to provide more detail on the concept. Thermal expansion also fundamentally alters the barrel’s response to resulting waves generated by gas pressure, recoil, bullet-barrel interaction interaction, and gravitational torque as barrel dimensions are continuously changing with heat.
2.6 Variable Heat (Q)
While heat variable Q has minimal effects on the system’s rigidity at minimal round counts, extended firing sequences adds non-linear heat values Q₁ + Q₂ + Q₃ + Qₙ into the system, causing the barrel to become increasingly susceptible to flexion due to changes in material stiffness. An example of this is identifying groups opening, losing both precision and accuracy, on extended round counts. The prime temperature gain Q₁ describes detonation, pressure, and friction, but each subsequent Qₙ segways into greater and greater contributions from atomic friction and the work done to accelerate the barrel to greater and greater amplitudes. This increasing Q variable affects barrel stiffness and thereby reduces precision and accuracy.
2.7 Heat and Material Failure
The work converted into thermal energy not only increases atomic vibration, the time an atom oscillates from its neighboring atom per Lennard-Jones Potential, but it changes material stiffness (modulus of elasticity) and other properties that affect its response to force load. Once a force impulse wrought by flexion exceeds the material’s stiffness provided by its temperature moment, material failure ensues.
3.1 Non-linear Acceleration
The work done to accelerate a barrel about its center axis can also cost valuable kinetic energy (K = 1/2•m•v²). Knowing no system is absolutely rigid with zero energy loss, projectiles must accelerate through a dynamic system, causing irregular accelerations given the bullet must momentarily straighten an imperfectly straight bore under non-uniform load. “The barrel [itself] is initially slightly deflected downward due to gravity [torque]. When the round is fired, the pressure also tends to straighten the barrel. As the barrel straightens, it over shoots in the upward direction and this adds to the excitation of the Mode 1 vibration. As a side note, the axial extension vibration mode is also probably heavily excited.” – Al Harral’s Barrel Tuner Analysis. This concept is further expanded on in Ep. 057 of the Hornady Podcast discussing ‘One Hole Groups? Dispersion’.
3.2 Ballistic Coefficient (BC)
Accelerating the barrel about its axis not only costs energy, but it can also affect BC, the ability for a projectile to resist drag. The following is an exert from Sierra Bullets 2.4 Lessons Learned from Ballistic Coefficient Testing:
“Theoretically, the BC of a bullet depends only on its weight, caliber and shape. But in a practical sense, the measured BC of a bullet also depends on many other effects. The gun can affect the measured BC value in two important ways: spin stabilization and tip-off moments. A bullet is gyroscopically stabilized by its spin, which is imparted by the rifling in the barrel. If a bullet is perfectly stabilized by its spin, then its longitudinal axis (which is also its spin axis) is almost perfectly aligned with its velocity vector. If a bullet is not perfectly stabilized (which is usually the case), the bullet may not be tumbling, but its point undergoes a precessional rotation as it flies. In previous editions of Sierra’s Reloading Manuals we have described this precessional rotation and have called it “coning” motion to aid in mental visualization of the motion. As the bullet flies, the point rotates in a circular arc around the direction of the velocity vector. Coning motion results in increased drag on the bullet, and any firing test method then yields an effective BC value for the bullet that is lower than the theoretical value. We have never been successful in accurately predicting BC values, or determining these values by any method other than firing tests.”
1. Longitudinal axis
2. Velocity vector
3. Nutation
4. Precession
ψ Yaw
Image credit
“Not only is the muzzle exit angle changing in time, but the muzzle is also moving in the vertical direction while the bullet is traveling down the barrel. When the bullet exits the muzzle, the bullet will have the same velocity as the muzzle.” – Al Harral’s Barrel Tuner Analysis. One of the most basic evaluations, in finite terms, is given bullets have length, they cannot be evaluated as a finite point. Thus, bullets will almost always have nutation, precession, or yaw of some degree due to a barrel’s acceleration about its center axis from gas pressure, recoil, and the interface between the bullet and the barrel. This is the precise reason load development embodies finding an amplitude where barrel velocity and the resulting tip-off moment is minimal.
Bullet Points
Advantages
Temperature Reistance
• Structured Barrels exude +300% more surface area for heat dissipation compared to a conventional barrel, so end users can shoot longer and run cooler. The high surface-area-to-volume ratio preserves material stiffness for greater performance in prolonged engagements and overall longevity, while also dramatically reducing mirage, barrel drift, and velocity migration.
Increased Stiffness
• Structured Barrels are +50% stiffer than a conventional barrel of the same weight, so end users can send faster, more accurate follow-up shots. Calculated in an independent analysis using MSC/NASTRAN, a state of the art program in the aerospace engineering world, various physics and engineering equations used to define an object’s second moment of area, or resistance to bend, corroborate the massive gain in rigidity.
Minimal Weight
• Structured Barrels are comparable in weight to a conventional barrel, and 21% lighter for the same stiffness. Click here to use drop-down menus to build a barrel and output a raw weight without exterior finishes or gunsmithing.
Ballistic Stability
• Precisely follows trajectories calculated by Kestrel with Applied Ballistics software with little to no truing.
Finishes
I-Beam
• Deep-holes radially drilled around the bore of a large DIA, monolithic blank to harness axial compression.
• Axial compression describes tensive and compressive forces exerted on an object to make it bend. I-Beam drilling creates a host of tubes that work in series as an ideal structure to reinforce the bore. As one hole bends, one side undergoes tension and the other compression. This triggers the hole opposite of it in the pattern to undergo compression and tension, 180 degrees out of sync. The opposing force vectors significantly reduce flexion and the work converted into thermal energy.
• The I-beam pattern locates the majority of material far from the bending axis, to withstand flexion forces. creating a much larger second moment of area, a much larger have larger moments of inertia, making said cross section considerably more difficult to bend when force is applied.
Vents
• Vent holes configured in a spiral pattern near the throat induce concentrated, convection cooling. Negative pressure generated at the muzzle pulls columns of high-velocity air through the neck of the barrel with each shot, cooling it from the inside-out. Velocity may exceed 50 fps (10 m/s).
*Suppressors alter the location of this low-pressure zone, dampening this phenomenon.
Cryo
• Aligns metallurgic molecular structures to reduce material micro voids, tears, and or overlaps for enhanced material stability.
Dimple | Add-on
• Cores milled around the chamber and perpendicular to the I-Beam structure for vibration dampening and weight reduction.
Fallen Angel | Add-on
• Multi-directional threads cut at random lengths to resist surface translated frequencies and further increase surface area to +500% compared to that of a conventional barrel.
Sandblast | Add-on
• Creates millions of microscopic surface depressions for a matte finish to reduce glare (ideal for snipers) and increases surface area.
Break-in and Maintenance
Break-in
Follow the below steps for lapped barrels. Failure to do so will will affect the barrel and its performance.
- Use Tubb’s break-in bullets from the TMS Kit (caliber specific).
- Load six (6) burnishing bullets from the TMS Kit at 60-75% of charge, lubing each bullet with Imperial Sizing Wax, Hornady One Shot, or equivalent, and set the seat depth so bullets do not engage the rifling.
- Thoroughly clean and remove particulates from the bore using a brush and patches; this will require significant brush-force due to adhesion forces.
- Shoot three (3) burnishing rounds.
- Thoroughly clean the barrel using a brush, patches, solvents, and detergents until you get a clean patch to prevent driving unwanted material into the barrel’s porosity.
- Shoot the remaining three (3) burnishing rounds, and proceed to thoroughly clean the barrel using a brush, patches, solvents, and detergents until you get a clean patch.
Complete. At this stage, there should be a lead into the lands and any burrs from throat operations removed.
Maintenance
• Repeat steps 1-5 as necessary for intervals will vary according to caliber, pressure, and bore conditions. Borescopes are highly recommended to guarantee a comprehensive and consistent bore cleaning.
Conventional vs. Structure
Conventional
vs.
Structure
MIL Review
“So the platform [300 Norma MRAD with +2,500 rounds] is not ideal. The weapon has issues with plastic parts and ergonomics; however, the barrel has performed better than any barrel I have used or shot against. Every person that shoots with me or against me is looking to see how to get their hands on one. With the 300 Norma, heat mirage is non-existent with your barrel and it gives me better clarity on the 1,000m plus shots. So, to answer your question, the rifle performs because of the barrel (….) I am standing very strong behind the barrel and its advantages.”
Follow-up – “I have been running my Structured Barrel for approximately 5-mo, and I’m pleased to say it has lived up to what I expected from a high-end, precision rifle barrel. When I was first introduced to the barrel, I was extremely skeptical and, like most, I had my doubts (….) That being said, I moved forward at this point with two barrels. One in my personal rifle chambered in 6mmCM and the other in a 300 Norma. I choose the 6mmCM, because I wanted a round I could compete, but also test the barrel life experience.
So far, I have completed multiple sniper matches at the highest level, and I am truly impressed. The recoil impulse as well as the heat dispersion is unparalleled. It only became apparent to me after shooting it. It’s one thing to explain to people – the different feel – and another to just put them behind the rifle for the experience. Anyone who has shot a polymer pistol and for the first time ever racked the slide on a custom 2011 will know the difference. The feel can only be explained by experience.
The barrel helped me and my sniper partner win the Army vs. Marine Grudge Match, and tie for third place overall at the Major Land Sniper Cup. This barrel has continued to play a huge role to my success and I can’t recommend them enough. During the course of fire, I have subjected the barrel to multiple high strings of 10-12 round groups with zero drift or displacement. This was confirmed on a match this past weekend, when I shot two 5-round groups into a target, then a 5-round group into a half-MOA square under the timer. Every round stayed well within the half-MOA square. Out to distance, once all the data is put in the Kestrel, it always tracks and lines up with my holds. I have no doubt in my mind when I take the shot that everything is doing what it was designed to do. This freedom gives me more time to concentrate on stage plan or whatever gear I need to prepare for the upcoming stage.
I have currently settled on a hand-load, strictly for velocity. It seems the barrel couldn’t care less what powder charge or bullet I use. It just flat out shoots them all same hole. Makes load development a thing of the past, and gives me more rounds during competition and less at a zero target under a chronograph.”
Long-range Competitor Review
“I now have 2 Structured Barrels with almost 1,000 rounds on them each. There are 3 things I believe to be particularly useful that I observed with my first barrel. They were enough to talk me into a second barrel, and my observations were still true.
Harmonics – The barrels does not seem to have any harmonic nodes. Which was the most surprising thing to me. I was able to zero the rifle and test ammo, all ammo of varying bullet weights and velocities, all grouped in the same POI. Also, I could never get a 90gr A-tip to fly right until I got your barrel.
Heat – The barrel never gets hot under normal shooting conditions. There have been a few competitions where I had to fire 20-rounds in a 2-minute engagement, and the barrel is still cool enough to grab. My partner’s barrel was untouchable for 15 minutes under the same conditions. The Structured Barrels also seem to cool faster.
Weight – They look like big, meat barrels, but they’re actually quite light for their size. I have shorter and smaller profile barrels that weight almost 2-lbs more than my Structured Barrels.
.22 NLR Competitor Review
“The first 10-rounds with the SK were one hole. One thing became very obvious to me is the ES/SD impact shows immediately, but that was it. The rifle wants put everything in the same hole. It’s like watching a video game through the scope. No recoil, no movement, nothing just deadness.
Groups at 100-yds | POA 2/10ths high:
+ 1st row CX .001RO | Avg .1675″ | Corollary Avg 1065 SD 6.7
+2nd row Midas+ no RO | Avg .268″ | Corollary Avg 1068 SD 11.4
+3rd row XACT no RO | Avg .276″ | Corollary Avg 1049 SD 8.9
+4th row Tenex no RO | Avg .272″ | Corollary 1107 SD 8.1
*RO – Run out
Δ58 FPS
Honestly, the rifle outperformed every ammo I fed it. It needs to go to Lapua and Eley for testing in their tunnels to find an ammo lot that will deliver the best SD’s. It was amazing shooting across the radar. I could tell based on where the impact went whether the velocity was high or low. I did have some ammo I was testing an Olympic runout gauge on, and the ammo performed best. And it was .001RO. I still need to shoot the .000’s I have, those will tighten up the group even more (….) Twenty years of research shows that for every .001″ of run out equates to 1/10th group size. The barrel is outstanding, and shows quickly the weak point is in the ammunition. Even though it’s Olympic ammo.
The velocity gained has been consistently 30fps, and that’s with a 4″ longer barrel than prior. ES has been cut in half and are consistently low single digits with match ammo. Shooting at a Dalt of about 7,500-ft in 95-deg weather, the Lapua SLR ammo was ~1150fps (spicy), but the groups at 200+ were incredibly tight.” – Chris Baxter
5-Round Groups from Four Different Manufacturers
PRS Competitor Review
• 3,000 Round 6mmCM Structured Barrel
• 30-round group from a Structured 6mmCM with +3,000 rounds and three (3) different factory ammos shot every 30-35s
Bottom group Sig Sauer 107gr Marksman
Middle group Hornady 108gr ELDM
Top group Barnes 112gr match burner
Coastal Precision
10x 5-Round Strings per Barrel Manufacturer – Total 50 Rounds
Temperature Readings of a conventional barrel
Temperature Readings of a Structured Barrel
