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About .223 Penetration

by R.K. Taubert

About the author: A recently retired FBI Agent with over 20 years experience in SWAT and Special Operations, he conducted extensive counter-terrorism and weapons research while in the Bureau.

Reprinted and edited with permission.

Close Quarter Battle Reputation
Several interesting but inconclusive articles examining the feasibility of the .223 caliber, or 5.56x45mm round, for CQB events, such as hostage rescue and narcotics raids, have recently been featured in a variety of firearms and police publications. However, for more than 20 years, conventional law enforcement wisdom generally held that the .223 in any configuration was a deeply penetrating round and, therefore, totally unsuited for CQB missions in the urban environment. Partly because of this erroneous, but long held perception, and other tactical factors, the pistol caliber submachine gun (SMG) eventually emerged as the primary shoulder "entry" weapon for the police and military SWAT teams.

Although new revelations about the .223 are beginning to slowly circulate throughout the Special Operations community, a number of law enforcement agencies are in the process of acquiring the next generation of "advanced" SMGs in 10mm and .40 S&W calibers. Could they and the public be better served by a .223 caliber weapons system and at less expense? Please read on and judge for yourself.

FBI Ballistic Tests
As a result of renewed law enforcement interest in the .223 round and in the newer weapons systems developed around it, the FBI recently subjected several various .223 caliber projectiles to 13 different ballistic tests and compared their performance to that of SMG-fired hollow point pistol bullets in 9mm, 10mm, and .40 S&W calibers.

Bottom Line: In every test, with the exception of soft body armor, which none of the SMG fired rounds defeated, the .223 penetrated less on average than any of the pistol bullets.

These tests were conducted by the FBI’s Firearms Training Unit (FTU), at the request of the Bureau Tactical and Special Operations personnel. Located at the FBI academy in Quantico, VA, this is the same unit with the encouragement of forensic pathologist Dr. Martin Fackler and other ballistic experts, that dramatically advanced the testing of modern handgun rounds to estimate their wounding effectiveness and potential lethality. Ultimately, this entity confirmed that permanent crush cavities, or "wound-channels," and deep penetration were the primary factors for handgun-fired projectiles. The FTU further determined that under various target engagement circumstances, a depth of penetration in soft tissue of between 12 to 18 inches was required for a handgun bullet to be effective.

Equipment Employed / Rounds Tested
For these series of tests the following firearms, ammunition and equipment were employed:

• Sealed, match grade test barrel to determine 25 yard, 10-shot group accuracy and 20-round velocity potential.
• 20" barreled, M16A1 rifle to stabilize and test rounds ranging from 40 to 55 grains in weight.
• 20" barreled, M16A2 rifle to stabilize and test rounds ranging from 62 to 69 grains in weight.
• Oehler Model 85 chronograph.
• Ransom type rifle rest, with laser bore sighting.
• Numerous blocks of Kind and Knox 250-A, 10% gelatin, to simulate living tissue.
• Federal’s 40-grain "Blitz" hollow point, 55-grain soft point and 69-grain hollow point; 9mm 147-grain Hydra-Shok, 10mm and .40 S&W 180-grain, jacketed hollow points.
• Winchester’s 55- and 62-grain full metal case, NTO-military spec. rounds.

As indicated, both rifles were fired from a mechanical rest. Ten-shot groups and 20-round velocity tests were fired for each round. 13 penetration tests were conducted. 95 rounds were fired for each type of round tested. A total of 760 rounds were tested and recorded for this project.

Test Protocol
Tests 1-6:
Bare gelatin, heavy clothing, automobile sheet metal, wallboard, plywood, and vehicle windshield safety glass, were shot a distance of 10 feet from the muzzle. The vehicle safety glass was set at an angle of 45 degrees to the horizontal, with the line of bore of the rifle/SMG offset 15 degrees to the side resulting in a compound angle of impact for the bullet upon the glass, which simulates a shot directed at the driver of a car closely missing the shooter. Furthermore, the gelatin was covered with light clothing and set back 18 inches behind the glass. All gelatin blocks, with the exception of the body armor barrier, were set 18 inches behind each solid obstacle shot.

Tests 7-13:
All involved shots through heavy clothing, safety glass and bare gelatin at 50 to 100 yards, concluding with internal walls, external walls and body armor at 10 feet. Test eight however, involved safety glass at 20 yards, shot dead-on, without the 15 degree offset, to simulate a shot at a car’s driver bearing down on the shooter.

For the connivance of the reader, test results are summarized in the following chart. Please note that the data displayed represents the average penetration of these rounds as measured in 10% ballistic gelatin (see tables 1 and 2).

Considering that the average person’s torso is 9 inches thick, front to back, all the .223 rounds ranging in weight from 55 to 69 grains appear to be adequate performers on soft targets where frontal shots are involved. Although the majority of target engagements are frontal, profile shots can and do occur. A .223 round that is required to pass through an arm before entering the rib cage mat, upon striking bone, fragment, and while possibly shattering the appendage, would most likely not be successful in producing a sufficiently deep body cavity wound to be decisive. In this, as with any CQB encounter, "controlled pairs," or rapid-repeat hits may be required to ensure target neutralization.

Defeating Ballistic Garments
Soft body armor appears to have little effect on the calibers ability to penetrate and actually seemed to enhance the 40-grain Blitz’s depth of penetration in soft tissue.

From a law enforcement standpoint, the ability of the .223 caliber round to defeat soft body armor, military ballistic helmets and many ballistic shields is a "double-edged sword." The criminal use of body armor is rare, but increasing. Possessing the ability to penetrate and adversary’s protective vest is obviously desirable. However, this round will also defeat law enforcement vests, so great care must be exercised in laying out and observing fields of fire in training and during operations. With this concern over potential fratricide in mind, voices have been raised in some quarters regarding this bilateral tactical attribute. A number of veteran officers strongly embrace The traditional concept that a department’s duty rounds should not exceed the capabilities of their vests. Arguably, this is a sound approach for any law enforcement agency to take for its non-tactical response personnel. However, SWAT, because of its specialized missions, may be a different matter and this later concern, while important, should not dominate the rationale supporting weapons selection by highly competent tactical units.

Although it has been reported that less that 1% of all serious crimes involve long guns and less than 8% of long gun related crimes involve rifles, law enforcement is being confronted more frequently by criminals with weapons and munitions that are capable of defeating all but the heaviest ballistic protection. The FBI’s Uniform Crime Reporting Section indicates, for example, that rifles were involved in 13% of the assaults on police officers during 1992. The incident a Waco, Texas, is a recent example of this problem. For forced entry teams, the need for higher levels of ballistic protection is essential.

For safe training of specialized law enforcement teams, the development of a lead-free, low penetration, short-range 5.56mm/.223 caliber training round that will (1) not penetrate ballistic vests and helmets, (2) destroy "shooting house" walls, (3) crater, or perforate steel-reactive targets, is extremely important. Fortunately, it appears that private industry is responding to these demands and such munitions are currently being developed.

Vehicle Interaction
With the exception of the full metal case and the 69-grain JHP rounds, it appears inadvisable to select lighter weight, soft or hollow point versions of this caliber when automobiles are likely to be engaged during planned raids and arrests. Penetration against automobile windshield safety glass is generally very poor and is only slightly better on sheet steel. Although terrorists from the insurgent New Peoples’ Army were able to blast their way through an armored limousine in the Philippines and murder a highly regarded U.S. military official with concentrated M-16 rifle fire, the SMG-fired pistol round demonstrates at least a theoretical, if not practical, edge against such hardened targets.

Interestingly, while penetration on auto glass and sheet steel is marginal, .223 projectiles will readily perforate and breach mild steel such as standard pepper poppers, that pistol rounds will only slightly dimple. However, very little of the .223’s mass is retained, so after defeating mild steel, significant wound potential is severely diminished upon exit.

Barriers and Structures
The Bureau’s research also suggests that common household barriers such as wallboard, plywood, internal and external walls are also better attacked with pistol rounds, or larger caliber battle rifles, if the objective is to "dig out" or neutralize people employing such object as cover or concealment. Although it is usually not advisable to fire at targets you can’t see in urban settings, it is done and some subjects have been stopped in this manner. Conversely, the ability of some pistol rounds to penetrate barriers tested puts innocent bystanders and fellow team members at greater risk in CQB scenarios. If an operator misses the intended target, the .223 will generally have less wounding potential than some pistol rounds after passing through a wall or similar structure. The close range penetration tests conducted indicated that high velocity .223 rounds were initially unstable and may, depending on their construction, disintegrate when they strike an object that offers some resistance. When concrete, brick or macadam are struck at an angle at close range, .223 rounds tent to fragment or break up, and ricochets are generally less hazardous. The .223 could consequently be considered safer for urban street engagements, because of its inherent frangibility within the cross-compartments created by street environments. In other words, in most shootings, the round would probably strike something, hopefully a hard object, break up and quickly end its potentially lethal odyssey.

As a point of interest, the rifled shotgun slug, while not possessing the .223’s flat trajectory, is still capable of attaining a maximum range of 900 yards. This fact illustrates that any errant law enforcement round regardless of caliber, or maximum range, is potentially dangerous to the community.

.223 Wounding Characteristics
Ballisticians and Forensic professionals familiar with gunshot injuries generally agree that high velocity projectiles of the .223 genre produce wounds in soft tissue out of proportion to their calibers, i.e. bullet diameter. This phenomenon is primarily attributed to the synergistic effects of temporary stretch cavity (as opposed to the relatively lower velocity stretching which typifies most pistol rounds) and bullet fragmentation on living tissue.

Distinguished forensic pathologist Dr. Martin L. Fackler, observed when he was conducting wound research for the U.S. Army several years ago ("Wounding Patterns of Military Rifles," International Defense Review, Volume 22, January, 1989), that in tissue simulants such as ballistic gelatin, , the 55-grain, M-193 military bullet lost stability, yawed (turned sideways) 90 degrees, flattened and broke at the cannelure (groove around the bullet into which the cartridge case is crimped) after penetrating about four to five inches. The forward portion of the bullet generally remained in one piece, accounting for 60% of its originally weight. The rear, or base portion of the bullet, broke into numerous fragments that may also penetrate tissue up to a depth of three inches. Dr. Fackler also noted that a relatively large stretch cavity also occurred, violently stretching and weakening tissue surrounding the primary wound channel and its effect was augmented by tissue perforation and further weakening by numerous fragments. An enlarged permanent cavity significantly larger than the bullet diameter resulted by severing and detaching tissue pieces. However, as the range increases, the degree of bullet fragmentation and temporary cavitation decreases because terminal velocity diminishes. At 100 meters, Fackler observed that the bullet, upon penetrating tissue, breaks at the cannelure, forming two large fragments. However, beyond 200 meters, it no longer looses its integrity, although flattening continues to somewhat occur out to 400 meters.

In his study, Fackler remarked that in abdominal shots, "There will be increased tissue disruption (beyond the bullet diameter wound channel) from the synergistic effect of the temporary cavitation acting on tissue that has been weakened by bullet fragmentation. Instead of observing a hole consistent with the size of the bullet in hollow organs such as the intestines, we typically find a void left by missing tissue up to three inches in diameter." However, "unless a extremity (peripheral hit) is sufficiently thick like a thigh, or the bullet does not strike bone, the round may pass through an arm for instance, causing little damage from a puncture type wound."

Regarding NATO’s 62-grain FMC M-855 (SS109) .223 caliber round Dr. Fackler observed that the bullet produces a wound profile similar to the M-193’s, particularly where abdominal or thigh wounds were involved. Other sources indicate this bullet, with a [steel] core penetrator, exhibits 10% greater fragmentation and retains its ability to fragment at slightly longer ranges than the 55-grain military bullet. [Keep in mind that the M-855 round, because of its steel core, has a length comparable to a 73-grain lead core bullet, and should be shot out of longer barrels (18+ inches) with tighter twists in order to retain good practical accuracy],

Hollow and soft point bullets in this caliber can be expected to upset and fragment much sooner and more consistently that full metal case (FMC) bullets. In light of this more consistent performance, Fackler recommends hollow points over "ball" ammunition for police use, providing the HP bullet penetrates deep enough to disrupt something vital. However, in his candid opinion the most effective round currently available for law enforcement operations is the 64-grain, Winchester-Western, pointed soft point, currently referred to as "Power Point". This bullet has a heavier jacket than those tested by the FBI, resists hyper-fragmentation, penetrates well and "expands like a .30 caliber rifle round." Subsequent FBI tests of this round fired from Colt’s 14.5-inch barreled Mk-IV carbine bore this out and bullet expansion was "impressive."

Dr. Fackler also advised that the synergistic effects of fragmentation and high velocity temporary cavitation cannot be scientifically measured in gelatin because that medium is too elastic. More Accurate results can be obtained by examination of fresh animal tissue soon after it is shot.

Range Limitations
Federal’s Blitz round, because of its very high velocity, low weight and frangible construction, demonstrated extremely poor overall penetration in the FBI tests. If it is considered for CQB use, it should be fired from ultra-short barreled weapons, such as Heckler & Koch’s, 8.85-inch barreled HK-53. Shorter barrels would bleed off excessive velocity to reliably fragment and produce good temporary stretch cavities at close range. Because of this velocity loss, the maximum effective range on personnel would most likely be 100 yards or less. To ensure that .223 caliber bullets perform as previously described by Dr. Fackler, it appears that a minimum target striking velocity of 2,500 feet per second (fps) is required. Bullets over 50 grains in weight may not accelerate to this critical velocity in barrels less than 10 to 11 inches in length. Tactical teams should therefore carefully select the appropriate barrel length for their CQB weapon, to ensure that the round they employ will deliver minimum terminal ballistic velocities at the ranges desired and balance it against maneuverability requirements [Also remember that dr. Fackler’s data is based on the FMJ ball ammo results and that hollow point ammunition will be as effective with lower velocities]. "Bull pup" configured carbines, such as the Steyr AUG, enjoy a distinct advantage here, because they retain long barrel lengths with relatively compact overall dimensions and are as flexible as an SMG in confined areas. In fact, a Steyr AUG compares favorably to H&K’s MP5-SD SMG in overall length and with a 16-inch barrel, is only an inch longer overall than a 14-inch barreled Remington 870 raid shotgun.

[At this point, Mr. Taubert’s article goes into extreme range shooting and barrel length. His suggestion is to have a barrel at least 14-18 inches long for CQB use as this allows for useful terminal ballistics at around 150-200 yards with 60+ grain bullets. I disagree with Mr. Taubert’s point of view for the simple fact that we are discussing Close Quarters firearms, and not long range sniping firearms. In these instances, a barrel length of 6-10 inches is practical for entry team use as it allows for greater maneuverability and acceptable ballistic performance with 55-grain hollow point ammunition. Also, a lot of Mr. Taubert’s information is based off of Dr. Fackler’s research using FMJ ammunition. Most of my information is based upon real-world shootings and actual testing of commercial ammunition in short barreled firearms designed for this application.]

A recent review of major U.S. ammunition manufacturers’ pricing indicates that commercially loaded .223 ammunition is slightly less expensive than similarly configured premium hollow point pistol ammunition. With millions of rounds of surplus military .223 ammunition possibly available to law enforcement, because of numerous base closures and through low cost channels, training with this caliber could be highly cost effective.

The .223 carbine is able to satisfy both close and intermediate range requirements and presents a good argument for eliminating the necessity for the law enforcement SMG. This one-gun concept will not only stretch departmental funds in this respect and reduce training requirements, but in some cases the difference in price between a single-fire carbine and a select-fire SMG often amounts to several hundreds of dollars. The need for full automatic fire with the M-16 carbine is debatable and two single-fire versions can often be purchased by police agencies for the cost of one top-of-the-line SMG. [This is a fact that I have been preaching for a long time. Another fact that Mr. Taubert does not touch on is that the M-16/AR-15 family of rifles use a split receiver system that allows the rapid exchange of differently configured uppers. This allows one officer to carry a 16" CAR-15 in is patrol vehicle as his secondary firearm, and a 6" upper receiver unit in his trunk for tactical entry use]

As a result of contemporary research, such as that conducted by the first FBI’s Wound Ballistic Workshop, some law enforcement agencies have expressed the opinion that concerns about pistol bullet over penetration were exaggerated. They cite the toughness and flexibility of the human skin in resisting bullet exit and the fact that police officers historically missed their intended targets most of the time in actual shootings. While poor hit ratios and over penetration may not be critical to some for individual gun battles that occur in the street, these marksmanship realities can become real planning and safety concerns when establishing fields of fire during raids, hostage rescues and other tactical operations.

Typically, these operations involve confined areas, where officers occupy positions in close proximity to each other. In close combat operations, every round expended must be accounted for. It is imperative that that rounds fired hit their intended targets and not pass through them to endanger other officers and innocent bystanders. If misses occur, it is desirable that once the stray round strikes a solid object, it expends its energy and disintegrates into relatively harmless pieces. If deep, barrier penetration is necessary, special ammunition or projectiles [or weapons] possessing this attribute can be selected.

Shootout Results
It was late in the morning on a hot July day in 1993, when members of a major Western cities’ police tactical unit executed a search and arrest warrants in connection with a narcotics raid on a "biker residence." The tactical officers were armed with Sig-Sauer 9mm P-226 pistols and 16-inch barreled Steyr AUG .223 caliber carbines with optical sights. The Steyr, loaded per SOP, with 28 Federal 55-grain HP rounds was the primary entry weapon for several officers on the team. Steyr carbines were selected for this raid, because the team leaders anticipated shots "out to 25 yards."

The team was required to knock and announce, effectively negating the element of surprise. Approximately 92 seconds into the raid, the officer involved in the following shooting incident was in the process of cuffing a subject when two Rottweiler dogs attacked. While the other officers were dealing with the dogs by employing OC aerosol, a 6-foot-tall, 201-pound subject, high on "speed", suddenly burst into the room occupied by the police through a locked door and leveled a 9mm pistol at one of the tactical officers. The distance between the adversaries was approximately 20 feet. With his back essentially to the subject, the involved officer acquired the threat in his peripheral vision, whirled around and commanded, "Police, put your hands up," while clearing the Steyr’s safety and mounting the weapon. The subject then shifted his pistol, held by one hand in a bladed stance, towards the reacting officer. In "less than a second" the subject’s hostile action was countered by the officer by firing two fast, sighted, tightly controlled pairs, for a total of four rounds at the subject. Rounds one and two missed, but were contained by the structure. Round three connected, penetrated and remained in the subject. Round four grazed his upper chest and exited as he spun and fell. Round three was quickly effective. The collapsing subject ceased all motor movement and expired within 60 seconds. The involved officer was aware of each round fired and simultaneously moved to cover. Tactical members were then confronted by a female accomplice armed with a double-barreled shotgun. However, the involved officer also successfully negotiated her surrender. All .223 rounds that missed the subject struck parts of the building’s internal structure, fragmented and remained inside.

When the autopsy was performed, the forensic pathologist was amazed at the degree of internal devastation caused b the .223 round. There was a two-inch void of tissue in the chest, with a literal "snowstorm" of bullet fragments and secondary bone fragments throughout the upper left chest area. The round struck the subject 11 inches below the top of his head and inflicted the following wounds:
  • Penetrated the top of the left lung, left carotid and subclavian arteries.
  • The collar bone and first rib were broken. Cavity measured 5x6 centimeters.

What is significant about this "instant one-shot stop" was that the round did not strike the subject at the most effective or optimum angle and did not involve any direct contact with the heart or central nervous system. It is doubtful that this type o terminal ballistic performance could have been achieved by any of the police service pistol/SMG rounds currently in use.

Although this is only one incident and could be an aberration, police tactical teams require this type of terminal ballistic performance to enhance their safety and survival particularly during CQB engagements, when criminals most often enjoy a positional and action-versus-reaction time advantage.

The FBI study clearly demonstrates the following: (1) that .223 rounds on average, penetrate less than the hollow point pistol rounds evaluated, (2) concern for over penetration of the .223 round, at close range, has been greatly exaggerated, (3) with the exception of soft ballistic garment penetration, the .223 round appears to be relatively safer for employment in CQB events than the hollow point bullets tested.

Observations and experience indicate that high velocity rifle bullets generally produce more serious wounds in tissue than pistol bullets, regardless of range.

Violent temporary cavitation, in conjunction with bullet yaw and fragmentation, are essential wounding components for high velocity rifle projectiles.

As range and bullet stability increases and velocity decreases, rifle caliber wound severity decreases and penetration increases.

Where soft target penetration requirements exist and over penetration concerns are prevalent, police should employ hollow point bullets in this caliber.

Full metal case or heavier soft point bullets may be more appropriate for hard target penetration in this caliber.

The .223 and the current carbine systems available for it are highly versatile and well suited for urban as well as rural operations. However, because of enhanced terminal ballistic performance, rifles are recommended if targets are expected to be engaged beyond 200 meters. [The .223 round itself should not be used in law enforcement applications at any ranges outside of 300 yards/meters. Long distance shots should be left to highly trained sniper units using medium caliber center fire rifle ammunition. e.g. .308/7.62 NATO. Also, the majority of police sniper shots occur within 100 yards/meters.]

The ability to train with one shoulder weapon and caliber for both CQB and open air options simplifies logistics and training, makes training more effective and is cost effective. [Again, one upper for general, secondary weapon usage, and one upper for CQB]

Under current pricing, police agencies can realize significant savings by purchasing single-fire carbines instead of select-fire machine guns.

Because of the "political" considerations and perhaps the concern over the possibility of more serious injuries caused by errant "friendly fire," the highly versatile and powerful .223 carbine may not be a suitable CQB firearm for some departments. However, if the above factors are not involved, the .223 carbine is an extremely flexible and effective anti-personnel weapon with, in many cases, handling characteristics actually superior to many contemporary SMGs. It offers the advantages of reduced logistics, lower costs and reduced training time when compared to agencies employing multiple specialty weapons. The caliber in its current offering is far from perfect, but in spite of some shortcomings, I anticipate that in the future it will eventually replace pistol caliber SMGs in many police departments and law enforcement agencies.

It has been a recently growing trend to see law enforcement departments exchanging their issue shotguns for the police carbine in 9mm, .40 S&W, and .45 ACP. And many departments have found that these carbines do not serve their needs as they expected. However, they are fearful to switch, or in many cases purchase, .223 carbines because "they will go through 10 people and 3 city blocks before they stop!" As you can see, this is not the case, and is in fact, completely the opposite. I hope that this article helps to clear all false truths and misnomers about this very versatile and serviceable cartridge.


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