• Ken Kraushaar

Terminal ballistics

Disclaimer: the following is for informational purposes and does not constitute legal advice with regards to ballistics, terminal ballistics, or any other firearms related issues. Ken Kraushaar firearms service assumes no liability for the information contained herein and enthusiastically recommends that you seek appropriate legal counsel if you need such representation and information.

Good morning all,

I hope your week has been safe and sane with regards to our chosen hobby of interest.

it's been pretty common with regards to shootings, that we get a lot of internet warriors taking what medical professionals say about treating firearms wounds, and then attempting to make the case for banning certain types of ammunition based off of their use in said shootings, and based off of an assumed dangerousness of one type of ammo versus another.

Case in point, the 223/5.56 used in AR-15's versus "Civilian" cartridges, such as the 308 winchester, the 30-06, and other larger more dangerous rounds, and how, supposedly, the smaller round is more dangerous because it "does more damage."

This blog hopes to address it with technical information. for reference, the sources I've used to compile this information are:

  • Ballistics: Theory and Design of Guns and Ammunition by Donald E. Carlucci and Sidney S. Jacobson

  • Hatcher's notebook- By Julian Hatcher

  • Engineering Design handbook- Ballistic Series: Interior ballistics of guns AMCP 706-150

  • Us Army Weapons command Research and Engineering Directorate: Small Arms Laboratory- Technical notes: Small Arms Weapons Design by John G. Rocha

  • Hornady Reloading Guide Volume 10

  • Ballistic Advantage ballistic Calculator by Bryan Litz

  • Data from the most commonly used ammunition brands for 223, 308, 30-06

  • data from the most commonly used military ammunition makers for 5.56, 7.62x51, 30-06 Springfield.

  • Gunshot wounds: A review of ballistics related to penetrating trauma - Panagiotis K. Stefanopoulosa, Georgios F.Hadjigeorgioub, Konstantinos Filippakisc, Dimitrios Gyftokostasd

  • Gunshot wounds: practical aspects of firearms, ballistics, and forensic techniques (2nd edition) - Vincent J. DiMaio, M.D.

note: this article is very long, and very boring, and will contain quite a bit of technical information. if you are here looking for a one stop shop for evidence for copying and pasting online- please stop right now, as it is very important that this information not be taken out of context.

The question of lethality seems to come up every time we have a shooting. purpose and intent of firearms is also questioned. we hear a lot of talk of "weapons of war" but fail to recognize where a lot of the popular rifles we know and love came from. which cartridges were or weren't around prior to their introduction into military service, etc. so first, there a history of the 5.56 and the AR 15 is in order.

In terms of the 223 / 5.56 nato, the cartridge is used commonly in hunting rifles (bolt actions) and was around prior to the advent of the M16/AR-15, and had been in use since 1963 in the civilian market (developed in '62), and used in a pump action centerfire rifle (remington model 760) when first developed; it is still used in that capacity in bolt rifles today, but it wasn't originally a military round to begin with.

It was actually chosen by the military because of lighter weight, meaning you can carry more ammo than you could previously, not because it was more dangerous than rounds previously used by the military (30-06 Springfield, 308 Winchester / 7.62x51 nato) which were larger, and moved just as fast as the 5.56/.223 Remington, but didn't allow for the same amount of ammo to be brought into combat with the soldier. so the military made a trade off which was to have more ammo available over a larger more effective round.

This is also why the Armalite Model 10 was rejected and redesigned into the model 15 (which then became the M16) , because the model 10 had used the 7.62x51nato (308) rifle round, and was a bit more robust, and thus did not meet the weight restrictions required by the military at that time. The battlefield was vastly different than what they encountered in WWII and they were forced to adapt after what was encountered in Korea, namely, that the M1 Garand, and the later M-14, were too heavy for the types of terrain that was being encountered.

If we're being honest, the reason it's used today by a lot of people, is because it doesn't take a whole lot of skill mastery to be able to shoot with it. the gun is light weight because it's primarily aluminum in construction, the recoil is minimal (when using a .223/5x56) which means it's easier to train, easier to master, and you can carry even more stuff along with you.

Hunters enjoy them because they are light weight and can be configured in other chamberings that make them good deer guns, hog guns, etc, not unlike what servicemen did when they converted old German Mausers to sporters, or conducted similar modifications to their service rifles, such as the 1903 Springfield; it's what they were used to using, and they needed them to be lite weight to carry in the field.

In a lot of cases, people like John G. Rocha, who was part of the US military small arms lab in the 1960s, weren't even thrilled with the design, based off of notes and lectures he gave on firearm design, and actually preferred a different, uglier looking firearm design in place of it, mostly because the soldiers tended to waste ammo because the original M-16 design didn't have select fire, and was full auto. John G. Rocha preferred Select / burst fire system which was present in another experimental program. This was later adopted was then adopted and you have what's been in use since.

Currently the military has vacillating between wanting to spend money on a modern design to replace the M4 and M16 chambered in 5.56nato because it's range is limited in the combat arena, and soldiers are being engaged at distances with which the 5.56 is lacking in, and then cancelling the project, and then going back again, because our troops have issues with its lack of effectiveness in terms of range and lethal power.

The AR-15 (the semi automatic version we know today) was changed significantly, internally, before it was allowed to be released to the general public , even though externally, there's very little difference to the untrained eye. There are 6 different parts which were changed or eliminated in the civilian model before it was allowed to be released on the market. these parts include:

  1. the selector switch

  2. the disconnector

  3. the trigger

  4. the hammer

  5. the removal of the auto sear and the camming pin hole

  6. the bolt carrier.

Honestly, the AR-15 doesn't function any differently than a mini-14, or mini-30, or even a 10/22. and isn't any more deadlier than the mini-14, or mini-30, it just looks different.

So basically it comes to a weight, ease of use, and ammo affordability that tend to make it popular, not because it is somehow deadlier than rifles with larger caliber rounds.

now the question comes to ballistics, because things like muzzle velocity are being thrown around in terms of somehow translating into more kinetic energy imparted upon flesh in the case of a .223 vs. a .308

In the 223, the kinetic energy of the bullet is 1,430ft/lbs. The muzzle velocity of a 125gr 308 winchester (larger round) is also 3100lbs for a heavier bullet and has a kinetic energy of 2,668 ftlbs at the same 100yard increment. it simply is bigger, has more mass, has larger cavitation when it impacts something, and hits harder.

but how do we explain how a 308's exit wound may be smaller than a .223?

The Short answer to the question is because of the lack of mass and exit velocity, it would be more prone to causing cavitation due to "yaw" or tumbling, but it also depends on the geometry of the bullet being used, i.e. whether it's a hollow point (which would expand), full metal jacketed, solid slug, hollow, semi-jacketed, or has a steel penetrator. In the case of a semi jacketed bullet, for instance, the radial stresses upon impact as it enters the target, expands, and then theoretically causes a more extensive wound., whereas a full metal jacketed bullet (such as say a bullet used for target shooting) would pass more cleanly through and not be effected in the same way. It all depends on what type of bullet in the cartridge / ammunition is being used.

To put it more simply, the 223's ability to be immediately affected is greater due to lack of mass, while the 30 caliber wouldn't necessarily be, and would pass through more readily (i.e. go through one target, and still have the potential / velocity, etc. to do damage to another, as you shown by the effect a 30 caliber rifle had during the assassination of president Kennedy, where Governor Connely was also hit by the same round, according to some forensic reconstructions of that incident,.) From a sheer physics based standpoint, It just depends on when the bullet becomes unstable enough.

A longer more scientific answer:

The longer scientific answer is a bit more complicated and technical because it involves fluid dynamics, aerodynamic drag and other scientific information :

The external ballistics would account for the muzzle velocities, etc. but where terminal ballistics is concerned, it's a matter of how hard it hits, and how much the bullet is or isn't slowed down, and materials used. Meaning you still get nasty cavitation with "civilian" guns. I've seen predator hunters that use a bigger tool than is needed for the job, such as a 308, or even worse, a 300 ultra magnum, and they too blow apart predators such as coyotes, even worse than a .223/5.56, but they do it out past the maximum effective range of the smaller round.

Regardless of caliber, you also end up dealing with other factors too. A projectile's primary means of incapacitation is through laceration, so because of the complicated nature of the human body, a projectile can do anything from causing minor bleeding if no major organ or artery is damage, to rapid death if a vital organ is impacted. if a projectile impacts bone tissue, or even meets a severe gradient in density, it can be deflected considerably.

When a projectile enters a human body, it sends stress waves through the body. these waves and associated rarefactions can cause damage, but its generally agreed in the ballistics community, that these waves primarily cause nerve damage and possibly collapse organs.

The temporary cavity that you can see in a lot of videos on youtube when they shoot ballistics gel is caused through cavitation, which basically results from the adherence of fluid molecules to the surface of the projectile, and when the shear stress drops to zero on the surface, the flow separates. that flow bubble can then expand to 40 times the projectile diameter as the projectile passes thorough the body, but once it has passed, it immediately collapses to a smaller size (what is known as the permanent wound cavity.) It is a common misconception that this temporary cavity is the major cause of incapacitatation, but it's not, and it is suggested that less than 20% of all tissue damage is due to the temporary cavity. Instead, it is the permanent wound cavity which causes the incapacitation with tissue damage being proportional to the kinetic energy transferred to the target by the projectile, and it is found that is the permanent wound cavity, which causes a majority of the damage due to inelastic deformation of the tissue.

This is also why ballistics gel, and even animal testing are not analogous to the effects a gun has on humans, as there's no current scaling law which has been determine whether or not the effect on humans vs gel vs animals is the same, since there are even differences between how a bullet reacts when it impacts an animal, versus how a bullet effects a human- they aren't the same, and the three different "targets" react differently to the same bullet.

In terms of the effect the bullet has upon impact, projectile yaw, or spinning, has a dramatic effect on permanent cavititation. Usually the projectile is unstable in the human body, and causes it to yaw considerably and potentially tumble. in the case of a smaller bullet, it may have more of a potential to yaw and tumble at closer range, and actually come out base first, which would account for the larger exit wound, but again, this depends on the action of the bullet inside the body.

The difference between the two sizes, (a .223" vs a .308" which is a matter of .085" difference in diameter, and 60 grn vs. 120grn (at minimum) which is 0.00857143 of a pound heavier) is that where the smaller bullet traveling at speed might be more prone to stresses depending upon materials used, and tumble more readily at close range, because it lacks the mass. The larger rounds do this and deal with the same instabilities, but would be more prone to passing through a target more readily and then tumbling and causing the wound at a further distance once it hits something, thereby transferring the larger kinetic energy after a greater distance. but again, this depends on the bullets being used.

A "varmint grenade " .223 vs. a ground hog would create a dramatic effect at 50-100 yards on the small body because of how it's designed, whereas a 300 ultra mag would be just as dramatic against a coyote at 1000 yards. Both rounds are overkill for their intent, and many times, the difference is in the distance, and both are lethal in their intended purposes, but these effects wouldn't necessarily be the same when the bullet impacted a human.

So again, what ends up making the difference is the kinetic energy transferred to the target. When the projectile yaws, it creates more surface area, so more of that energy is being transferred, but it's still only 1,430ft/lbs being transferred on a surface area that is .223" in diameter, and at best, even if it yaws, is only able to transfer that energy along a length of 2/3 of an inch in the case of a 70 grain bullet .223" diameter bullet.

The greater the initial kinetic energy of the projectile at impact, the more there is available to deposit into the target. the greater the kinetic energy, the greater the propensity for projectile deformation and breakup. if the projectile does not deform, too much kinetic energy may be viewed as undesirable as the projectile may pass through the target however , the target may still be incapacitated and may bleed to death.

more yaw at impact means that is more difficult to penetrate the target, if the projectile does penetrate the body, then the hole will be bigger and the projectile will drag down faster.

larger caliber and or blunter projectiles deposit more kinetic energy at the target because they have greater drag. projectiles that expand deposit more kinetic energy into the target. this is why there are projectiles that are designed to expand by using a hollow point, slit jackets, lower hardness cores, etc. higher drag projectiles deposit more kinetic energy into the target. the projectiles that fragment deposit more kinetic energy into the target as well. so the dangerousness of a larger round isn't any more or less than a smaller round.

Bullets in tissue:

there are differences too in how the bullet will react depending on the tissue it impacts, and many of the following will affect the bullet passage through a living creature. they include:

  • bone

  • skull and brain

  • thorax/ribs

  • lungs

  • intestine/stomach/bladder

  • muscle

each of these tissue types will have a different effect on the projectile. it is even important if the organ is flaccid, or not, or whether or not the target is living or dead. it is important to note that most general research is carried out on muscle tissue, and that is where a great deal of work has been done to come up with a suitable material for testing.

in the case of muscle tissue penetration, the first thing that must be recognizes is that it has a non-negligible tearing stress that must be overcome, and it is this additional stress that is incorporated in aerodynamic drag models on the subject. scholars who teach on the subject cannot emphasize enough how complex this problem is. in the case of muscle tissue, even though we assume a penetrating event into homogeneous muscle tissue, we also have to recognize that a penetrating event is much more complex than what a simple mathematical equation can state.

in this case, we know that as a projectile enters muscle tissue, what was once simple aeroballistics becomes more complicated and a problem of continuum mechanics: in air, there was no yield stress to overcome, the viscosity and density of muscle are different than air. if the impact angle is low enough, the nose of the projectile will enter first. the usual decrease in shear stress as we progress along the projectile will occur, and at some point the shear stress will reach zero, and the tissue will separate from the projectile forming a cavitation bubble. throughout the event, the projectile will slow down due to drag. there where also be a larger overturning moment than in air because of the large force on the small area of the nose (higher density in the dynamic pressure term,) and in addition the separation will take place ahead of the center of gravity, increasing the moment arm. the drag force will also include force required to overcome the cohesive stresses in the tissue (tearing stress) which is not usually present in aerodynamic models.

What was once a transonic/supersonic flow flow field becomes a transonic (at best). or subsonic flow field.

this is because the speed of sound in muscle tissue is around 1500 m/s (4920 ft/s)

In comparison to aerodynamic flow models you might encounter with regards to just aerodynamic flight, you have to use a drag model that accounts for tearing of the tissue.

The range at which a target is fired upon also affects the nature of the wound.

there are 4 types of contact:

-Hard contact- Muzzle pressed into the skin

-Contact- Muzzle touching the skin

-Near contact- muzzle very close to the skin



most of the time, you will find the 223 / 556 to be considered an intermediate round.

The intermediate range case is characterized by tattooing or stippling of red-brown or orange color. the victims may have propellant particles embedded in their skin. these particles are most prevalent when the cartridge used ball, cylindrical or single perforated grains. there may be grease or an abrasion rim. pistols, intermediate range is about 2-3 barrel lengths, for rifles, it's about 3ft.

the distant range is probably the one most encountered by military personnel. in most distant cases, there will only be a bullet hole present. it is possible to observe an abrasion or grease rim. a low velocity impact may exhibit a neat hole and a well defined abrasion rim while a high velocity impact may exhibit a hole with radiating splits. the presence of the abrasion rim is largely dependent on the aerodynamic shape of the bullet: a pointier projectile like a VLD yields less abrasion rim while a blunter bullet like a spire point yields more abrasion rim.

Centerfire rifle wounds at intermediate range can injure organs not in the direct path due to shock effects (although this is debated.) these cartridges create a very large temporary cavity. occasionally clothing imprints are found on the entry area. at distant range, these cartridges exhibit a behavior that is similar to that of an intermediary range. the entrance wound will usually be two to three times the bullet diameter, with the exit wound usually being larger than the entry wound.

so a .308 diameter bullet would leave a wound that is 1.232" in diameter as opposed to the .892" diameter of the .223" diameter bullet.

One of the common fallacies about assault rifles is that the wounds they

produce are more severe than those due to ordinary centerfire rifles. In fact, the wounds are less severe than those produced by virtually all hunting rifles

even the Winchester M-94 (introduced in 1894) and its cartridge the .30–30

(introduced in 1895).

In dealing with rifles, the severity of the wound is determined by the amount of kinetic energy lost by a bullet in the body. The intermediate cartridges used in assault rifles possess significantly less kinetic energy than a regular centerfire rifle cartridges designed for hunting. In addition, since most ammunition used in these weapons is loaded with a full-metal jacketed bullet, the wound is even less severe than one might expect.

The severity of a wound, as determined by the size of the temporary cavity, is directly related to the amount of kinetic energy lost in the tissue, not the total energy possessed by the bullet. If a bullet penetrates a body but does not exit, all the kinetic energy will be utilized in wound formation. On the other hand, if the bullet perforates the body and goes through it, only part of the kinetic energy is used in wound formation. Thus, bullet A with twice the kinetic energy of B may produce a wound less severe than B, because A perforates the body whereas B does not. This, of course, assumes the bullets follow the identical paths through the body.

Kinetic Energy loss:

The amount of kinetic energy lost by a bullet depends on four main factors. The first is the amount of kinetic energy possessed by the bullet at the time of impact. This, as has been discussed, is dependent on the velocity and mass of the bullet.The second factor is the angle of yaw of a bullet at the time of impact. The yaw of a bullet is defined as the deviation of the long axis of the bullet from its line of flight. When a bullet is fired down a rifled barrel, the rifling imparts a gyroscopic spin to the bullet. The purpose of the spin is to stabilize the bullet’s flight through the air. Thus, as the bullet leaves the barrel, it is spinning on its long axis, which in turn corresponds to the line of flight. As soon as the bullet leaves the barrel, however, it begins to wobble or yaw. The amount or degree of yaw of a bullet depends on the physical characteristics of the bullet (its length, diameter, cross-sectional density), the rate of twist of the barrel, and the density of the air. Angles of yaw have been determined with certainty only in military weapons.

The maximum angle of yaw at the muzzle may vary from 1.5degrees for a 150-gr. .30–06 Spitzer bullet, to 6 degrees for a 55-gr. .223(5.56 mm × 45) bullet.8 Extremes in temperature can increase yaw and thus the stability of the bullet.

Altering the rate of twist in the barrel or the weight of the bullet can also alter the angle of yaw. The AR-15/M-16, as originally designed, had a barrel twist of 1/14 in. (1/356 mm). This twist was too slow,however, so that bullets fired from the weapon were so unstable as to cause significant problems in accuracy. In order to correct this flaw and to stabilize the bullet, the twist rate was changed to 1/12 in (1/305 mm). While this twist rate was sufficient to stabilize the 55-gr. bullet, when the U.S. military adopted the 62-gr. bullet, this rifling was found to be too slow to stabilize the heavier bullet and the rifling was changed to 1/7 in. (1/178 mm)

The greater the angle of yaw of a bullet when it strikes the body, the greater the loss of kinetic energy. Because retardation of a bullet varies as the square of the angle of yaw, the more the bullet is retarded, the greater is the loss of kinetic energy.

As the bullet moves farther and farther from the muzzle, the maximum amplitude of the yaw (the degree of yaw) gradually decreases. At 70 yards,the degree of yaw for the 55-gr. .223 (5.56 × 45-mm) caliber bullet decreases to approximately 2 degrees. This stabilization of the bullet as the range increases explains the observation that close-up wounds are often more destructive than distant wounds. It also explains the observation that a rifle bullet penetrates deeper at 100 yards than at 10 feet. Although the gyroscopic spin of the bullet along its axis is sufficient to stabilize the bullet in air, this spin is insufficient to stabilize the bullet when it enters the denser medium of tissue. Thus, as soon as the bullet enters the body, it will begin to wobble, i.e., its yaw increases. As the bullet begins to wobble, its cross-sectional area becomes larger, the drag force increases, and more kinetic energy is lost.

If the path through the tissue is long enough, the wobbling will increase to such a degree that the bullet will become completely unstable, rotate 180 degrees and end up traveling base forward.Tumbling of a bullet causes a much larger cross-sectional area of the bullet to be presented to the target. This in turn results in greater direct destruction of tissue as well as greater loss of kinetic energy and a larger temporary cavity. The sudden increase of the drag force or tumbling puts a great strain on the bullet which may eventually break up. A short projectile will usually tumble sooner than a longer one.

The third factor that influences the amount of kinetic energy lost in the body is the bullet itself: its caliber, construction, and configuration. Blunt-nose bullets, being less streamlined than spitzer (pointed) bullets, are retarded more by the tissue and therefore lose greater amounts of kinetic energy. Expanding bullets, which “open up” or “mushroom” in the tissue,are retarded more than streamlined full metal-jacketed bullets, which resist expansion and lose only a minimum amount of kinetic energy as they pass through the body.The caliber of a bullet and its shape, i.e., the bluntness of the nose, are important in that they determine the initial value of the area of interphase between the bullet and the tissue and thus the “drag” of the bullet. Shape and caliber decrease in importance when deformity of the bullet occurs. The amount of deformation in turn depends on both the construction of the bullet (the presence or absence of the jacketing; the length, thickness, and hardness of the jacket material; the hardness of the lead used in the bullet;the presence of a hollow-point) and the bullet velocity. Lead round-nose bullets will start to deform at a velocity above 340 m/sec (1116 ft/sec) in tissue. For hollow-points, it is above 215 m/sec (705 ft/sec).10Soft-point and hollow-point centerfire rifle bullets not only tend to expand as they go through the body, but also shed lead fragments from the core .

This shedding occurs whether or not they strike bone. The pieces of lead fly off the main bullet mass, acting as secondary missiles, contacting more and more tissue, increasing the size of the wound cavity and thus the severity of the wound. Such a phenomenon, the shedding of lead fragments, does not happen to any significant degree with handgun bullets, even if they are soft-point or hollow-point,unless they strike bone. Breaking up of missiles appears to be related to the velocity. The velocity of handgun bullets, even of the new high-velocity loadings, is insufficient to cause the shedding of lead fragments seen with rifle bullets.

Often not appreciated is that full metal-jacketed rifle bullets may break up in the body without hitting bone. This phenomenon was not seen in the .30–06 (7.62×63 mm) M-1 round but gained considerable medical attention with the M-193, 55-gr., 5.56 ×45 mm, M-16 round ).

Because of this, there were press and medical reports stating that this bullet “blows-up” in the body. The M-193 M-16 bullet does tend to break up after penetrating the body, but it does not blow up. Although this round has a reputation for causing extremely severe wounds, the amount of kinetic energy lost by this round is less than that from the relatively low-velocity .30–30 (circa 1895) hunting cartridge.

The tendency of a full metal-jacketed bullet to break up in the body is governed by its velocity and tendency to radically yaw.

Yaw revisited:

When the bullet yaws significantly, its projected cross- sectional area becomes much larger,with a resultant increase in the drag force acting on the bullet. The sudden increase in this drag force puts a great strain on the structure of the bullet, resulting in a tendency to break up. All this causes a greater loss of kinetic energy with an increase in the severity of the wound. It has been observed that in the tendency of high-velocity, full metal-jacketed bullets to break up, that blunt-nosed bullets break up from the tip, whereas pointed bullets break up from the base.

In both types of full metal-jacketed bullets, the lead core can be squeezed out the base if the bullet is exposed to severe stress, due to tumbling. Breakup of the military M 193, 55-gr., 5.56 × 45-mm bullet initiates when it begins to yaw. The bullet tends to flatten on its longitudinal axis and bend t the cannula. The tip of the bullet remains relatively intact while the core and rest of the jacket shred and lead is expelled out the base.

Certain minimum velocities are necessary for this to occur. The bullets flatten at velocities in the low 2,000 ft/s range, breaking up in the mid to high 2,000 ft/s range.5Breakup of the 62-gr. version of this bullet is similar. The 7.62 × 51 bullet also starts to break up at the cannula.

The fourth characteristic that determines the amount of kinetic energy loss by a bullet is the density, strength, and elasticity of tissue struck by a bullet as well as the length of the wound track. The denser the tissue the bullet passes through, the greater the retardation and the greater the loss of kinetic energy. Increased density acts to increase the yaw as well as shorten the period of gyration. This increased angle of yaw and the shortened period of gyration lead to greater retardation and increased loss of kinetic energy.

Several authors have discussed the fallacy of describing the severity of gun shot wounds by means of the velocity characteristics of the penetrating missile. In the context of wound ballistics, “low-velocity” and “high-velocity” can only refer to the circumstances of wounding, indicating wounds from handguns and rifles respectively.

However, the use of such terms as estimates of the wound itself is inaccurate and potentially misleading, as it is based on the erroneous impression that the extent of wounding is directly proportional to the impact energy of the projectile, which is greatly influenced by its velocity according to the familiar kinetic energy formula (KE=1/2mv2). In fact, it is only the energy deposited to the tissues that is transformed to work resulting in tissue disruption. Although the effects of rifle bullets can be far more destructive compared to handguns because of their higher energy, almost all of these so-called “explosive” effects can be traced back to the phenomenon of cavitation, which as we've discussed, is a prominent manifestation of high-energy transfer. At the other extreme, a non-deforming (FMJ) rifle bullet traversing in stable flight a limited width of soft tissue will spend only a small fraction of its enormous kinetic energy.

Therefore, it is more appropriate to think in terms of energy transfer (or deposition) to the wound in order to outline its extent and severity rather than concentrating on the physical properties of the bullet.

the extent of tissue damage along the wound track may vary as a result of non-linear energy deposition. The rate of energy transfer to the wound is determined by the tissue resistance to penetration,which is affected by the frontal surface area of the bullet “presented” to the tissue.

The critical factor leading to higher amounts of energy deposition along the bullet track is any increase in the presented area, which invites drag forces of greater magnitude. There are two main mechanisms responsible for such an occurrence. With yawing, the presented area of the bullet can only enlarge;as the yaw angle approaches 90 degrees both the energy transfer and the resulting wounding effect increase markedly , as the bullet essentially severs tissue with all its length. The small-caliber bullets of the M16 and Kalashnikov AK-74 assault rifles yaw and tumble significantly earlier than the twice heavier bullet used by the ubiquitous AK-47 rifle, thus creating large wounds early in their path.

it's not that the round from the ak-47 is less dangerous than the .223, it's just that the heavier bullet, again, tends to be more stable, and not react in the same manner. the .223 is not more powerful, or has more available kinetic energy it's just more unstable.

One final point should be made about kinetic energy and temporary cavity formation. No matter how large a temporary cavity a bullet produces,it will have little or no effect unless it forms in an organ sensitive to injury from such a cavity. A 3-inch cavity in the liver is more effective as a wounding agent than the same cavity in the thigh muscle.

as you can see, from the information above, there is quite a bit of information as to why the smaller bullets do what they do, however, the argument in terms of how they are some how more dangerous or more powerful than a large rifle caliber isn't necessarily factual. you're dealing with physics, and aerodynamics and other things that can't easily be measured, and most experts in the field, which this information was studied and taken from , all refer to each other when talking about the topic.

what this boils down to is that there are several factors which determine when a bullet reacts in the way that it does, and it has to do with more than just the velocity, since velocity alone does not increase the area with which kinetic energy is transferred, but other factors, and even then, again a .223 does not have the same kinetic energy as a 308, due to the shear fact that the mass is not the same, so velocity and kinetic energy while contributing factors, aren't what determines what a .223 does in the body, nor does it make it more dangerous than a larger caliber bullet.

so sit with that information, digest it a little bit, and try to understand that what is being put out there by proponents of gun control in terms of lethality isn't scientifically factual.

stay safe, and happy shooting.

Ken Kraushaar is a Gunsmith and Certified Firearm Specialist in Sonoma County, CA.

he has over 30 years of experience and serves the larger north bay area.

Recent Posts

See All

notes on overpenetration

good morning all, hope this finds you well. I wanted to write some notes about this topic because it is garnering a lot of attention in terms of the raging debate about intermediate round rifles and t