Tactical Briefs #5, 15 April 1998
Prefragmented Bullets: Dangerously Inadequate for Personal Defense
MagSafe, Glaser, BeeSafe, Quik-Shok.
These cartridges propel a bullet that is designed to break apart into multiple subcaliber projectiles upon impact with a human body. The theory behind prefragmented bullets (PFB) such as these is the belief: 1) that the bullet will be more effective in stopping a criminal attacker because it very quickly transfers all of its kinetic energy, 2) the multiple subcaliber projectiles create a devastating shotgun-like wound, 3) the multiple penetrating subprojectiles increase the chances of hitting something vital, 4) if the bullet misses the bad guy whom its been shot at, it presents less of a hazard to other people because the bullet will disintegrate when it strikes a hard object, and 5) the bullet is unlikely to completely perforate an attackers body intact and thus it will be less of a hazard to other people who might be downrange.
PFBs Incapacitate via Rapid Energy Transfer?
Medical professionals who are deeply involved in wound ballistics research have been unable to identify any physiological mechanism in the human body which should cause a person to collapse unconscious after having been shot with a high energy projectile. Theyve found no evidence to support a "neural shock" theory in which a bullets temporary cavity (produced by the transfer of bullet energy to soft body tissues) will have a remote effect on the central nervous system that causes an attacker to instantly lose consciousness.
There are examples every day of people who absorb the equivalent or more energy transfer than generated by the impact of any of the handgun bullets listed above and are not knocked unconscious or somehow rendered unable to perform willful actions: a baseball outfielder whose entire upper body crashes onto the playing field after running as fast as possible and lunging with both arms outstretched to make a last second fly ball catch, motor vehicle collisions, police officers who are shot with high energy projectiles but protected by their soft body armor, physical mishaps of all kinds, beating victims, etc.
The blunt force sensation of energy transfer might possibly play a role in producing psychological collapse. The feeling of a hard hitting bullet slamming into his body might cause an attacker to believe that hes been very seriously hurt. This perception might cause him to voluntarily stop his aggression for survival reasons, or it might produce overwhelming mental distress that causes him to faint. He may even have the preconceived notion that hes supposed to fall down after being shot because hes seen actors who portray gunshot victims do this on television and in the movies.
An assailants psychological reaction to being shot is unpredictable. An attacker who is psychotic, chemically intoxicated, emotionally disturbed or acting with a very focused determination to cause as much harm as he can before hes stopped might not show any reaction to being shot and may be totally oblivious to the fact that he has been shot. THE ONLY RELIABLE WAY TO QUICKLY STOP AN ATTACKER IS TO DESTROY TISSUE THAT IS CRITICAL TO HIS IMMEDIATE SURVIVAL.
Multiple Penetrating Projectiles Increase Wound Severity and Chances of Hitting Vitals?
As a PFB disintegrates and the subcaliber projectiles are released to penetrate further, the multiple wound tracks produced by the penetrating fragments weaken the integrity of resilient soft tissues. In the area of maximum temporary cavity, which is usually located within the first 5-6 inches of handgun bullet penetration, these smaller wound tracks can be torn open by the subsequent stretching of soft tissues, worsening the injury. It is important to point out that there will be SOME tearing of soft tissues in the vicinity where the multiple subprojectiles begin to disperse, in the area where their separate wound paths are located close to one another. This added disruption is probably best described as a modest increase in wound trauma. But, due to the shallow location on the wound track where this increased disruption occurs (within the first 5-6 inches of penetration), a PFB is not going provide you any advantage in wounding effectiveness when compared to the wound trauma produced by a conventional JHP bullet that meets IWBA Handgun Ammunition Specifications.
As the small PFB subcaliber projectiles penetrate deeper into soft tissues their velocity decreases. This affects the amount of tissue that is crushed. As a projectile penetrates deeper and slows, it crushes an ever decreasing diameter of tissue in its path. The reason is because as velocity decreases, the ability of soft tissue to simply stretch around the edges of the penetrating projectile to get out of the way increases. In the last few inches of penetration, these subcaliber projectiles are producing extremely narrow wound channels.
To confirm this observation for yourself, you need only look at any of gunwriter Ed Sanows photographs (in Handguns magazine) of PFBs shot into blocks of ordnance gelatin. Youll notice the dye he uses to highlight the gelatin disruption doesnt seep down the very narrow wound channels produced by the subcaliber projectiles. The narrowness of the individual wound channels is most evident in his photographs of MagSafe bullets. Sometimes a wound channel isnt visible behind a pellet at all.
Projectile shape also affects the amount of tissue disruption. Spherical shaped shotgun pellets are less efficient in producing wound trauma. The smooth rounded shape allows elastic-like soft tissue to more easily stretch around the projectile, rather than being crushed. The shotgun pellets used in most PFBs produce tiny, pinhole-sized wound channels.
The three irregular-shaped fragment pieces of a Quik-Shok bullet are not aerodynamic, but this doesnt mean that theyll tumble end-over-end after they separate and chew their way through flesh. What these subcaliber projectiles do is quickly seek a state of stabilization in dense soft tissue. Once stabilization is achieved, the fragments continue to penetrate in a fixed (non-tumbling) orientation. (Triton is kind enough to publish a photo of their Quik-Shok wound profile in ordnance gelatin on their web site, but unfortunately theres no measuring device included in the photo to allow interested persons to determine the scale of the disruption. A link to Tritons Quik-Shok web page is provided at the end of this article.)
Under ideal conditions the multiple projectiles can be very damaging. A PFB that impacts and penetrates the unobstructed upper torso of an attacker will probably produce a severe injury, but so too will a conventional JHP bullet.
However, the dynamics of violent confrontation often produce less than ideal target engagement conditions, and a defender might not have the opportunity to make a perfect, unobstructed shot to the chest or head if shots to the body fail. Its not uncommon for a bullet to encounter an outstretched arm that is holding a weapon, or for a bullet to be required to negotiate an unusual penetration angle. Both of these scenarios require a bullet that penetrates deeper than the subcaliber projectiles of any PFB to reach and disrupt the vital cardiovascular structures needed to produce fatal hemorrhage that will reliably stop an attacker.
If you hold both your arms out in front of you as if you were holding a handgun in a two handed shooting grip, youll observe that a bullet will have to pass diagonally through approximately 4-5 inches of forearm muscle (assuming the bullet doesnt strike bone) before it exits to penetrate your chest. PFB subprojectiles would have to not only penetrate this much muscle tissue, they would also have to overcome the resistance of the skin to exit the forearm. Skin can present as much of an obstacle to bullet exit as 4 inches of muscle tissue. Although the skin on a forearm probably wont offer this much resistance to subprojectile exit, it will still subtract from the penetrating potential of each fragment that exits the arm.
A couple of examples of situations where your bullet might have to negotiate an unusually deep, but unobstructed penetration angle include the possibility of being knocked off your feet and having to fire at an attacker who is towering over you, or having to shoot an assailant from the side or an oblique angle through an arm or shoulder while coming to the aid of a loved one whos under attack.
Finally, it would seem logical that if the number of penetrating projectiles were increased that the chances of hitting something vital would likewise also increase. Were unaware of any cogent study that has specifically examined PFBs to determine whether or not the multiple projectiles increase the potential for damaging vital tissues. Were unconvinced there is any advantage due to the few number of subprojectiles released by PFBs, the shallow depth in the wound profile where maximal tissue damage is produced, the uneven penetration distribution of individual fragments and the narrow wound channels crushed by the subprojectiles.
Do PFBs increase the odds of disrupting vitals? This theory is based on the belief that the wide lateral dispersion of the subprojectiles increases the chances that one or more fragments at the outer radius of the distribution pattern will damage a vital organ that would have been missed by a single, large penetrating projectile. But what offsets any advantage gained by this capability is the relative mildness in severity of the resultant wound trauma produced by one or two small fragments that happen to stray into vital tissue. While inflicting a vital wound is the desired and intended goal, tissue damaged in this manner is not going to quickly force an attacker to stop. This capability does not adequately compensate for poor shot placement.
The erratic penetration distribution of PFB subprojectiles can also decrease the overall severity of a vital wound. The deepest penetrating fragments seem to be the ones that penetrate straight ahead. Consider the severity of wound trauma produced by a well placed shot where only one or two deeply penetrating fragments manage to intersect the heart, aorta or vena cava near the end of their wound paths. The holes crushed in the wall of the affected structure will be very narrow in diameter compared to the large single hole crushed by an expanded JHP bullet following exactly the same straight ahead trajectory through the body.
Do PFBs Minimize the Risk of Danger to Others?
Maybe, as long as a PFB penetrates flesh. If a PFB misses the bad guy entirely, its no less dangerous to others than a conventional JHP bullet. Theres no guarantee that a stray PFB will hit an intervening obstacle that will stop it or cause it to fragment into smaller, supposedly less dangerous particles. If it does breakup, is there a greater chance that the increased number of ricocheting fragments might strike and seriously injure others who are nearby?
With the exception of the MagSafe SWAT cartridge, PFBs typically remain intact and have the potential to penetrate several layers of plasterboard or other barrier materials such as sheet metal, glass and plywood. PFBs tested against common building materials used to construct dwellings demonstrate slightly less penetrating potential than conventional JHP bullets.
A PFB that hits an assailant off-center along the periphery of his body, producing a short through-and-through wound track that involves only a few inches of tissue penetration before exiting, will probably fragment and be slightly less dangerous to others than a conventional JHP following the same path.
A PFB that hits an attackers body squarely will be no less dangerous to others than a conventional JHP bullet that meets IWBA Handgun Ammunition Specifications. In this scenario, its highly unlikely that a PFB or a JHP bullet will overpenetrate an attackers body. A deep penetrating JHP bullet will most likely be retained inside the attackers body by the holdback effect of skin.
When you target an attackers torso with your bullet, the only way your bullet is going to reliably stop him is for it to destroy vital cardiovascular structures which are located deeply in his body. To stop him quickly your bullet must crush a hole in one of these structures to produce blood loss in quantity to force him to collapse unconscious. An attacker must lose at least 20 percent of his blood volume before it begins to affect the functioning of his brain. Therefore, unless you can predict the future with absolute certainty that you will have a clear, unobstructed front to back shot into a attackers sternum, the bullet you choose for personal-defense should be capable of inflicting wound trauma that promotes rapid fatal hemorrhage from any engagement angle.
PFBs do not give you this level of capability. The area of greatest tissue destruction produced by PFBs is located at a point that is too shallow in the wound track to reliably include blood bearing organs when less than ideal conditions are encountered.
The last few inches of a bullets wound track are the most important because this is where it is most likely to encounter vital tissues. The large expanded diameter of a deeply penetrating JHP bullet is going to produce much greater wound trauma when it passes through the heart or a major abdominal blood vessel than the subcaliber fragments of a PFB. Blood loss in volume to have an effect is going to take time. The single, larger diameter JHP wound will facilitate faster blood loss than the constricted wound channels crushed by PFB subprojectiles.
PFBs are less hazardous to bystanders than JHP bullets in theory only. However, if you keep a handgun for home defense and youre concerned about wall penetration, then the MagSafe SWAT cartridge is the only choice that meets your requirements for limited wall penetration. None of the other cartridges discussed in this article are designed to fragment as they pass through wallboard. The tradeoff for this limited penetration of interior walls is significantly lessened wounding effectiveness.
For concealed carry, if you live in a jurisdiction that outlaws JHP bullets and youd feel more comfortable loading your gun with a PFB instead of non-expanding ammunition, the non-hollowpoint design BeeSafe might be worth considering.
Bullet selection for personal defense should be directed toward choosing one that possesses the qualities that will make it effective over a wide range of scenarios because this will increase your chances of survival when the unusual happens. The most important quality is penetration because a handgun bullet cannot damage what it does not touch. If the bullet you shoot into an attackers body doesnt pass through a major blood bearing organ, theres no reason why your bullet should suddenly compel him to stop whatever hes doing thats endangering your life or the life of a loved one.
Despite the marketing claims of the companies who manufacture these bullets and the assertions of gunwriters who are preoccupied with velocity and energy transfer, PFBs do not reliably penetrate deeply enough nor produce the kind of wound trauma that is needed to quickly and reliably stop a determined attacker, and this is why we feel theyre dangerously inadequate for personal defense.
Estimating Handgun Hollowpoint Bullet Penetration Using the MacPherson Water Test Method
MacPherson's water test method1 enables you estimate handgun ammunition terminal performance, using bullet weight, velocity and expanded diameter data obtained from shooting hollowpoint bullets into water with your handgun, and makes it possible for you to determine suitability of any particular JHP bullet cartridge for personal defense use. Materials required to perform testing are commonly available.
The following procedure is based on the work of IWBA member Ron Jones, and which is published in the IWBA journal, Wound Ballistics Review.2
55 gallon steel barrel (or deep metal trash can) filled full of water
Calipers, dial or digital (preferably capable of measuring in millimeters, however measurement in inches can be converted to millimeters by multiplying measured value by 25.40)
Scale (capable of measuring unit weight in grains)
MacPherson book 3
1) Using chronograph, measure velocity of at least 10 cartridges fired from test gun to determine average velocity of gun/cartridge combination.
2) Fire 10 JHP bullets (from same lot of ammunition as in step 1) vertically into center of water-filled container. Pause long enough for air bubbles to clear after each shot. Theres no need to stop to recover each bullet. You can recover the bullets all at once after youve shot the last one. (You will get wet doing this, but you can minimize the splash by placing an old bed sheet over the mouth of the water-filled container.)
3) Recover bullets from water-filled container. Using calipers, measure average expanded diameter of each bullet using instructions on page 251 (JHP Bullet Expansion) of MacPhersons book.
4) Calculate average expanded diameter for all 10 bullets.
5) If expanded diameter was measured in inches, multiply average expanded diameter measurement by 25.40 to convert measurement to millimeters. Otherwise proceed to step 6.
6) Using scale, measure post-expansion weight of each recovered bullet.
7) Calculate average post-expansion weight for all 10 bullets.
8) Consult Figure 10-6, JHP Bullet Penetration Curve Definition (page 252), to determine which of the 5 curves match the average expanded diameter and average post-expansion weight of your bullets.
9) Consult Figure 10-7, JHP Bullet Penetration Depth (page 253), to estimate penetration depth by matching the curve identified in step 5 with the average velocity measured in step 1.
- MacPherson, Duncan: "JHP Bullet Penetration," Bullet Penetration -- Modeling the Dynamics and the Incapacitation Resulting from Wound Trauma; p. 251. Ballistic Publications, El Segundo, California: 1994.
- Jones, Ronald L.: "Water Testing .38 Special +P Hollow Points." Wound Ballistics Review 3(1); 13-16: 1997.
MacPherson, Duncan: Bullet Penetration -- Modeling the Dynamics and the Incapacitation Resulting from Wound Trauma. Ballistic Publications, El Segundo, California: 1994.
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