Interesting article I came across. Forgive me if it has been posted before, but I thought I would share w/the board. Enjoy.

223 for CQB
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.

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.

Defeating Ballistic Garments
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.

Vehicle Interaction
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.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. 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.

.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.
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.

Range Limitations
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.

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. 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. 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. 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. 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.

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 overpenetration 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.

In summary 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.

Not many people here will find this as "news". It's a "water is wet" report to most.

Agree. But always nice to have good empirical study to back up what you know when you run into the eventual "know it all - know nothing."

Don't need to read it to know to 5.56 fucks shit up all day long. The round does some crazy things to a human body.

I appreciated OP

Interesting read

Wow...anyone that thinks 5.56 is a deeper penetrating round that 9mm ball should not be in a possition to select equipment.

Most anyone here could have told you so 15 years ago. The only real issue with issuing 5.56 -- is setting one off in a confined space without a suppressor. Its painful!

I'm a believer in 12 guage for CQB; specifically a 14" Benelli Super 90. I cant really think of anything else i'd rather have.