Science Behind G9's Shape Charge Technology

Science Behind G9's Shape Charge Technology

Posted by Bo Johnson on 24th Mar 2023

What makes G9 Defense's solid copper fluted rounds superior to Jacketed Hollow Points and other defensive handgun ammunition? 

G9's solid copper or brass projectiles have flutes or channels and are non-expanding bullets, in contrast to other traditional self-defense handgun rounds. Their designed destructive mechanism is contact tearing and fluid transfer through the Venturi Effect. The flutes or channels constrict and concentrate the liquified tissue impacting the bullet accelerating the fluid and reducing the dissipation of the liquid by creating a jet of focused high velocity material. Fluted bullets lower the Terminal Ballistic Coefficient, increasing drag, which increases cast-off fluid velocity through constriction IAW Bernoulli’s principle and the Venturi effect. Recent testing has proven that fluted solid metal bullets transfer fluid at approximately 30% projectile velocity (cast-off speed).This is compared to less than 10% from hollow points or FMJ.

This concentrated high-speed liquid tissue cast-off destroys adjacent tissue through direct impact. This is not energy transfer temporary stretch cavity which doesn’t destroy tissue. Temporary cavity is caused by a low-density compressible wave travelling at approximately 100 fps (10% projectile velocity).Constricted fluid transfer is high density (over 1,000 times more dense) non-compressible liquid travelling at over 450fps. This is particle vs wave physics3.

This fluid transfer is direct contact high-speed fluid on live tissue. Remember that liquified tissue under high pressure is what causes the expansion of the hollow point by tearing the metal walls and overcoming the frictional forces. With this design, increased velocity of any round increases wound volume. Cast-off velocity must be high enough to not just impact adjacent tissue but to destroy it. Velocity of the cast-off is a percentage of the projectile velocity and the bullet is slowing throughout the metasoma what point is the velocity of the cast-off too low to create wounding? How deep does the wounding from the fluid transfer actually occur? Modern Law Enforcement water cannons can propel water at rates up to 20 liters per second, and can stream water 67 meters away. The velocity of the water decreases at increased range. The velocity of water where tissue destruction occurs is approximately 60 meters per second. (200 feet per second) / (120 mph). This velocity is determined to predict a safe distance that a water cannons water velocity will not cause serious tissue damage (tearing). 45

A change of fluid from water to a higher density or viscosity fluid will have a corresponding increase in damaging effects.6 Blood is 3% denser than water (1025 kg/m3 vs 997 kg/m3). Viscosity is measured in the unit of centipoise (cp).The viscosity of water is 1 cp and human blood serum viscosity relative to water is 1.8 cp.7 For a liquid of 1.8 cp and 103% density to have the same force as water traveling at 200fps it must travel 140 fps. At that cast-off velocity human skin will be torn and destroyed. Cast-off velocity of the Solid Metal Fluid Transfer (SMFT) Fluted rounds is approximately 30% of the rounds velocity. To achieve 140 fps cast-off velocity the projectile must be traveling 470 fps.

The coefficient of drag (Cd) of an object stays the same if the shape and media its traveling through stays the same.8 FMJ and SMFT are linear, non-profile changing rounds and the Cd is constant. These rounds exhibit a linear decrease in velocity over distance.(Hollow points, frangible and tumbling rounds change their profile through expansion, turning and fragmentation which greatly change the Cd.)

The average muzzle velocity of a SMFT round is 1500 fps, therefore 70% of the penetration depth is caused by a projectile that has sufficient velocity (140 fps) that the liquid tissue cast-off causes tissue tearing. After that percent of penetration, the wound size will equal the diameter of the projectile. Another effect that adds to Fluid Transfer causing damage and destroyed internal tissue even more than the above figures show is that the above figures for the velocity of water required to tear tissue was calculated for law enforcement to ensure that the water does not tear the skin of the target. Internal muscle tissue and organs have a lower tensile strength than skin. “Results: The full-thickness skin strips had a median tensile strength of 604 N/cm. The tensile strength of the muscle fiber was between 110 N/cm and 43 N/cm, depending on the muscle. 9 This is in direct correlation with the FBIs finding that “The skin is tough and flexible."

Experiments have shown that it has the same resistance to bullet passage as approximately four inches of muscle tissue.”10 Therefore, the cast-off velocity required to destroy internal tissue is far less than what is required to tear through all the layers of skin. Unfortunately, no actual velocity for internal tissue destruction is available. It is more probable that the actual percentage of penetration depth where the fluid transfer causes internal tearing is 90% or more. This Is also shown in testing with animal tissue, during live animal shooting (hunting) post-mortem dissections and forensics reports of humans after a gunshot wound with a Solid Metal Fluid Transfer (Fluted) round, where the diameter of the wound exceeds the diameter of the projectile through deeper penetration depth .Lastly, since they are solid and don’t expand about the only failure is turning or tumbling which stops the designed fluid transfer. A turning round of this type will create a substantially smaller wound diameter and also less deep penetration than normal.

Penetration: The depth of penetration for these rounds is between 16-20 inches during the FBI series gel tests for determining penetration depth. Penetration depths are very consistent for all projectile weights and calibers.

Reliability / Consistency: Fluid Transfer rounds have a high reliability and consistency rate. Tumbling or turning was witnessed in less than 10% of the rounds tested in both gel and tissue, with and without barriers. When witnessed, this tumbling was almost always at the end of the penetration depth where the negative effects of tumbling are less detrimental. Whereas traditional hollow point point ammunition fails over one third of the time in gel. <Handgun bullets (hollow points) expand in the human target only 60-70% of the time at best. Damage to the hollow point by hitting bone, glass, or other intervening obstacles can prevent expansion. Clothing fibers can wrap the nose of the bullet in a cocoon like manner and prevent expansion.11

Barrier Performance: Fluid Transfer rounds exhibited a reduced effectiveness of 5-15% when encountering light domestic barriers. When encountering heavy barriers, the reduction was the least,<20%,of any of the 5 bullet types and there were almost no deviations in trajectory.

Permanent Wound Cavity: Liquefaction and then constriction through the venturi effect causes a jet of high-speed liquid tissue into surrounding tissue outside of the diameter of the projectile with sufficient force to cause tearing and add to the permanent wound cavity caused by the surface area of the bullet.The wound diameter for these rounds always exceeded the diameter of the projectile proving that the fluid transfer is effective at destroying adjacent media. This was shown in gel as well as animal tissue with and without barriers. It has also been witnessed in hunting encounters and real-world forensic data on live human targets. All of the examples tested create holes of a larger diameter than any hollow point in the same caliber and with the deeper penetration have overall wound volumes (VWI) greatly larger than any of the other projectile types. It is true that in non-compressible gel the cavities created by the hydraulic effect are artificially large, on the order of 4-5 times the size of those created by hollow points in the same caliber. In actual tissue the wound volumes are roughly 150%-250% (2.5 times) that of hollow points in the same caliber.

Geophysical Research Abstracts.“Energy Dissipation During Wave propagation in Bimodular media.” Kuznetsova, Maria; Pasternak, Elena; Dyskin, Arcady. 2019, Vol. 21

Department of Justice,report.“Water Cannon-Police Weapons Center Report Series 4-70”LC Miller 1970.

OpenDemocracy,article."White-washing the water cannon:salesmen,scientific experts and human rights abuses". Anna Feifenbaum. 2014. Retrieved 15 July 2015.

Cardiology Physiology Concept.article.“Viscosity of Blood”Dr Richard E. Klabunde.2022

National Aeronautics and Space Administration(NASA).article“The Drag Coefficient”Tom Benson. 2021

National Library Medicine. Article.“Experimental Evaluation Of Fibre Orientation based

material properties of skeletal muscle tension”.Chetan D Kuthe, RV Uddanwadiker,Alankar Ramteke. 2016.

10 Fackler,M.L.,M.D.,Director,Wound Ballistics Laboratory,letter:“Bullet Performance Misconceptions”, International Defense Review 3, 1987.

11 FBI Firearms Training Unit, Quantico, VA. <Handgun Wounding Factors and Effectiveness.