“Incoming fire has the right of way." - Unknown

Structured Barrels


  • Harmonically dead
  • Little to no load development
  • Increased barrel life


Objects exhibit a natural vibrational frequency described by its harmonic mode, a function of material stiffness (modules of elasticity), mass distribution, and structural stiffness.  Wave functions originating from within an object look to propagate at a matching, fundamental frequency.  Sinusoidal waves that diverge from its natural frequency generate irregularities and non-repeating standing wave patterns that create vibrations.  Harmonics propagate efficiently through uniform objects.  Changing its mass distribution and structural stiffness will affect its mode and underline frequency while material stiffness is affected by temperature and force.


Force is derived by multiplying mass and acceleration, the rate velocity changes in respect to time.  Increasing acceleration increases the amount of force and resulting energy that can be transferred into an object through work.  Supersonic flexion, commonly referred to as barrel whip, describes rapid harmonic acceleration and since a barrel has mass the work done to accelerate this mass by tensive and compressive forces generates enormous energy.

The law for the conservation of energy states energy of an isolated system remains constant for it is neither created nor destroyed, only converted into different forms.  Therefore, the work applied to a barrel to undergo flexion converts into thermal energy and this principle for work to conduct thermal energy is described by the Carnot engine and is a fundamental thermodynamic concept for entropy, a high-to-low energy state.

Thermal Embrittlement

Thermal energy alters the orbital state of electrons and thus can change a material’s atomic, mechanical, vibrational, and thermal properties (among others).  This is known as a phase shift and is the reason material stiffness is affected by stress and subsequent temperature gains when force is applied to perform work.  Stresses that exceed an object’s state for material stiffness provided by its temperature moment will result in molecular/material failure, a phenomenon called thermal embrittlement.

Harmonic Modes

Material stiffness (modules of elasticity), mass distribution, and structural stiffness are functions that describe a barrel’s harmonic mode.  When a standard barrel undergoes whip, the system works to vibrate on a sinusoidal wave that matches its natural, fundamental frequency.  However, supersonic flexion yields diverging frequencies that make the barrel rapidly accelerate with irregular and non-repeating amplitudes.  The result stresses the barrel’s material stiffness and the work acted to whip the barrel is converted into thermal energy and is absorbed by electrons.  Heat raises orbital states, altering modules of elasticity and exasperating discrepant frequencies, and this makes the material more susceptible to thermal embrittlement.  Once the stress from supersonic flexion exceeds the material’s stiffness provided by its temperature moment, throat erosion, fire cracking, and gas jetting is caused by molecular failure.

Structured Barrels restrict this phenomenon by increasing a barrel’s harmonic mode and purposely configured to directionalize residual harmonic frequencies for cancellation.  Enhancing its structural stiffness and mass distribution (compared to a standard barrel of the same weight) restricts supersonic flexion and thus the work and stress converted into thermal energy.  This achieves superiorly more stable modules of elasticity for prolonged material stiffness and resists thermal embrittlement.  Structured Barrels are the culmination of many physics principles (harmonics, material acceleration, energy, and thermodynamics) working in concert for a harmonically dead barrel that requires little to no load development and exhibits increased barrel life.  See ‘ADVANTAGES’ for details.


• Shoot sub-1/2 MOA groups across grains from different manufacturers.

• Structured Barrels are 56% stiffer than a standard barrel of the same weight; calculated using aeronautical program, CEL.

• Weight is comparable to a standard barrel.  See ‘PROCUREMENT’ for details.

• Structured Barrels are 21% lighter than a standard barrel of the same stiffness, calculated by aeronautical program, CEL.

• Find a load in as few as 20 rounds shooting 10-grain ladder tests in 1/2-grain increments.

• Structured Barrels are 38% lighter than a standard barrel with the same frequency; calculated using aeronautical program, CEL.

• Achieve greater tolerance.

• Superior structural stiffness improves its stability across loads, setups (brakes and suppressors), and (atmospheric) temperatures.

• Reduce velocity migration to single-digit deviations for extended round counts.

• No vertical stringing.

• Gain precision.

• Harmonic treatments directionalize frequencies to be uniplanar for optimum cancellation.  The result is a smooth, muted recoil impulse that pushes straight back making it easier to spot your own rounds and reacquire the target.

• Increase barrel life.

• Thermal embrittlement is a phenomenon where materials undergo mechanical/molecular failure due to stresses affected by temperature and material elasticity.  Enhancing a barrel’s structural stiffness and mass distribution (compared to a standard barrel) restricts supersonic flexion and thus the work and stress converted into thermal energy.  This prolongs its material stiffness and prevents thermal embrittlement causing throat erosion, fire cracking, and gas jetting.  See ‘INTEL’ for details.


• Add +500% surface area.

• Material harmonics rapidly change with temperature.


• ~$1,000.

*Varies per barrel length and selected finishes.


• A deep-hole drill pattern around the bore that uniplanarizes frequencies and resists sinusoidal harmonics via axial compression for advanced recoil mitigation.

• Axial compression describes the tensive and compressive forces exerted on an object to make it bend.  Tubes are simple structures that oppose this event due to its ideal structural stiffness.  AUX drilling creates a host of tubes that work in series 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, and opposing force vectors cancel applicable x-y magnitudes.  This significantly reduces supersonic flexion and the work done to generate thermal energy. 

• AUX drilling is not a sleeve.  Thermodynamic expansion coefficient deltas from different materials induce systematic stress and changes in vibrational frequency.

• Breather holes configured in a spiral pattern near the throat induce concentrated convection cooling.

• Projectiles passing through the muzzle generate negative pressure that pull columns of high-velocity air through AUX-drill finish, cooling it from the inside.

*Suppressors alter the precise location of this low-pressure zone and will dampen this phenomenon. 

• Offset radii cored perpendicular to AUX drilling pattern around the chamber to sectionalize harmonics and impede vibrational frequency.

• Extracts pounds while maintaining maximum rigidity.

• Multi-directional threads cut in randomized sequences of length and pitch to resist surface translated harmonics and increase heat dissipation.

• Harmonics rapidly change with temperature.  Thermal entropy, a high-to-low energy state, flows like electric entropy to tips (corners, edges, etc.), areas with a high surface-area-to-volume ratio, to release excess energy and the Fallen Angel creates hundreds of tips forward of the chamber to rapidly dissipate heat.

• Adds +500% more surface area compared to a standard barrel.

• Microscopic depressions to increase surface area.

• Enhances heat dissipation and reduces harsh, distinguishable glare.


  1. Purchase a blank directly from tacomHQ at zero markup or from a manufacturer.
  2. Harmonically treat blank with finishes.  See ‘FINISHES’ for details.
  3. Chamber and thread blank with tacomHQ or another gunsmith.
  1. Bolt-Action
  2. Barrel Nut
  3. Desert Tech
  4. Carbines (coming soon)

Click here to order a blank from tacomHQ at zero markup and manufactured by Bartlein or Krieger (3-6 mo).

• Blanks sent from other manufacturers must match the following starting-diameters:
>/= .150 | 1-1/2″
>/= .338 | 1-3/4″
>/= .375 | 2″
>/= .460 | 2-1/8″

*Blanks serve as a deposit and will not require further transaction until received and we provide notice for “Step 2”.

Click here to select finishes (2-3 mo).

• Harmonic treatment will yield the following – final – diameters:
>/= .150 | 1-1/4″ to 1-3/8″
>/= .338 | 1-3/8″ to 1-5/8″
>/= .375 | 1-3/4″ to 2″
>/= .460 | 2″ to 2-1/8″

*Action OD (A), thread (B), and thread length (C) are not required until blank is received.

Click here for tacomHQ to chamber and thread at zero markup by Vestal Custom Rifles (1-2 mo)

• Blanks are machined +0.100″ when shipped to another gunsmith.

• Formulas estimate weight before chamber and threading (varies per selected finishes):
>/= .150 | ~.25 lb/in
>/= .338 | ~.30 lb/in
>/= .375 | ~.40 lb/in
>/= .460 | ~.50 lb/in

*For example, a fully-treated 26″ .300 PRC will weigh approximately 7 lbs (0.27 lbs/in x 26 in)

• Use the diameters provided in “Step 2” to select a chassis.

• Recommendations include Cadex, Tubb ATR, McMillan, McRees, MDT, and more.

Click here for an ITAR Category 1 export permit.

  1. Assuming a high-end lapped barrel, use Tubb’s break-in bullets from the TMS kit – caliber specific. 
  2. Five sets of bullets will be provided with your kit.
  3. Load ten bullets at 75-85% of charge and lube each bullet with Imperial Sizing Wax, Hornady One Shot, or equivalent to reduce seating pressure.  Set seating depth so the bullets do not engage the rifling.
  4. Thoroughly clean the bore using a brush and patches to remove particulates; this may require significant brush-force due to adhesion forces.
  5. Shoot five rounds.
  6. Thoroughly clean the barrel using a brush, patches, solvents, and detergents for 30-60 mins until you get a clean patch.  This prevents driving unwanted material into the barrel’s porosity.
  7. Shoot remaining five rounds and repeat step 6.
  8. Shoot five Burnishing Bullets and repeat step 6.
  9. Shoot 10 rounds using your specific bullet at 85% charge (metallurgies vary between manufacturers) and repeat step 6.
  10. Complete.  At this stage, there should be a lead into the lands and any burrs from throat operations removed.
*DISCLAIMER:  Failure to follow these steps may cause inaccuracies.

• Repeat steps 1-6 as necessary for tune intervals will vary according to caliber, pressure, and bore conditions.

Made in the USA

Made in the USA