For several decades, FBI Agents carried the .38 caliber revolveras a standard firearm. Now, after extensive testing andevaluation, the FBI is converting to a new semiautomatic pistol. The new pistol, built to FBI specifications and chambered for anew cartridge⌐⌐the 10mm, will be issued to all FBI Agents toreplace existing revolvers. This article describes the processthat led to this decision.
BACKGROUND
The authority for FBI Agents to carry firearms was first grantedin 1934. Although pistols were sometimes issued or permitted ona limited basis, the revolver predominated as the FBI sidearm. The first significant shift occurred in 1981, when SpecialWeapons and Tactics (SWAT) teams were equipped with largecapacity 9mm pistols. Since then, 9mm pistols have also becomethe issue weapons for the FBI's Hostage Rescue Team (HRT) andspecial surveillance teams.
For the general Agent population, however, revolvers remainedthe issue weapon, though the increasing use of pistols reflecteda growing recognition that the modern pistol provides certainadvantages over the revolver. Primarily, pistols are generallymore compact and portable and provide a larger ammunitioncapacity. They are also quicker and easier to reload. Moreover, experience has shown that pistols are generally easierto shoot quickly and accurately due to the self⌐cocking operationof the slide following each shot and the more efficienttransmission of recoil. What is most important, however, is thatpistols have proven to be durable and reliable.
Undoubtedly, interest in pistols intensified when innovativedesigns of the weapon began to appear on the market during theearly 1980s. Whereas the basic revolver design remains much asit was at the turn of the century, the pistol has been virtuallyrefashioned in recent years, providing a wide range of suchinnovative features as double⌐stacked large capacity magazines,double⌐action triggers, ambidextrous controls, multiple safetydevices, and endless varieties of shapes and sizes.
Meanwhile, other events entered into the picture. Instanceswhere law enforcement officers were confronting more violent,heavily armed subjects appeared to be on the rise. Theincreasing
use of semiautomatic and even fully automatic weaponsby certain segments of the criminal element began to raiseconcerns about the adequacy of law enforcement armament.
SELECTION OF A NEW HANDGUN
In 1987, new impetus was given to the FBI's ongoing evaluation offirearms and ammunition. The Firearms Training Unit, located atthe FBI Academy in Quantico, VA, set out to identify the bestpossible handgun for FBI Agents. Firearms training expertsundertook a major testing project to evaluate a variety of 9mmand .45 caliber pistols then on the market. While several of thepistols tested were effective, none possessed all of the featuresdesired in a general issue FBI weapon. The challenge was todevelop a pistol that met the needs of the FBI. In themeantime, as a response to a growing perception within Agentranks that a pistol was preferable to the revolver, the Directorof the FBI authorized Agents to use personally owned pistols, either 9mm or .45 caliber, as long as the weapons were ofapproved manufacture and design and the training andqualification standards were met.
A Question of Caliber
The most critical, and controversial, issue relating to theselection of a new FBI handgun was that of caliber. Questionshave been raised not only about the adequacy of some weapons butalso about the wounding effectiveness of some ammunition. Caseaccounts of shootings document the fact that subjects receivingfatal, but not incapacitating, wounds have been able to returnfire and inflict further damage.
Wound Ballistics
As a means of resolving the problem, the FBI convened a WoundBallistics Seminar at the FBI Academy in September 1987. Theparticipants included noted individuals from the scientific andmedical communities from throughout the Nation who possessedrelevant expertise in the field of wound ballistics. One of theprimary purposes of the seminar was to identify the performancecriteria of a bullet most likely to inflict an incapacitatingwound on a human target.
A second purpose of the seminar was to determine, if possible,which of the two calibers, the 9mm or the .45, was likely to bemost effective in accomplishing that goal. And, although theseminar was unsuccessful in conclusively resolving the caliberquestion, it did identify the desirable performance criteria ofan effective bullet.
Incapacitation, in the law enforcement context, may be simplydescribed as bringing about the immediate cessation of hostile orthreatening activities. Incapacitation may result frompsychological or physiological factors. Psychologically, some
individuals are predisposed to fall down at the sound of gunfire,while others may continue to fight even though they areseriously-⌐even fatally-⌐wounded. Because a particular person'spsychological response to a gunshot wound cannot be predicted,ammunition performance must be viewed from the perspective ofphysiological incapacitation.
The seminar participants unanimously concluded thatphysiological incapacitation can be accomplished in one of twoways⌐⌐damage to the central nervous system (the brain or upperspinal column) or significant loss of blood. Because theplacement of a shot in the relatively small, highly mobile targetarea of the brain cannot be counted upon in an armedconfrontation, a bullet must therefore be capable of penetratingthe body sufficiently to pass through major arteries and blood-
bearing organs to ensure timely physiological incapacitation. Without adequate penetration, physiological incapacitation cannotbe attained. Given adequate penetration, the only reliable wayto increase the effectiveness of the wound is to increase itssize, thus increasing the amount of tissue damage and the rate ofhemorrhage. Thus, the FBI's test program was designed toevaluate bullet penetration and wound size.
Ammunition Test Design
With the performance criteria acquired from the Wound BallisticsSeminar, the next step was to design and construct a series ofammunition tests to measure the performance of different roundsagainst those standards. For that purpose, the Firearms TrainingUnit established a working group which included personnel fromthe Special Operations and Research Unit, the Hostage RescueTeam, and the Institutional Research and Development Unit.
The tests were designed to simulate factors realistically. Therefore, if the effects of bullets upon human tissue were to berealistically measured, a substance that would duplicate humantissue was needed. Based upon the research of Dr. MartinFackler, Director of the Army's Wound Ballistics Laboratory, atthe Letterman Institute in San Francisco, 10% ballistic gelatinwas selected to simulate soft human muscle tissue. Eightseparate penetration tests were conducted by firing bullets intothis substance.
Also, since experience demonstrated that bare tissue is seldomvisible on a target in a violent confrontation, seven of theeight tests included covering the gelatin with typical clothingmaterial (cotton T⌐shirt material, flannel shirt material, 10oz. down in a nylon carrier, and denim). To assure validity andstandardization, clothing manufacturers were consulted todetermine the average thread count in typical underclothing,shirts, and jackets.
Other factors were then considered. Because FBI Agentsfrequently confront subjects in vehicles, behind doors or walls,
and at various distances, clothed gelatin was placed behindwindshield glass, car door metal, plaster board and plywood. Again, manufacturers in the construction and automobileindustries were consulted to assure that the materials usedreplicated substances that bullets would have to pass through inreal⌐life situations. While most of the test shots were firedfrom a distance of 10 feet, some of the tests were conducted at20 yards to assess the effects of distance and velocity loss onpenetration potential.
Five shots were fired in each of the 8 penetration tests,providing a total of 40 shots for each caliber or bullet typetested.
The Competing Calibers
Once the tests were designed, a decision had to be maderegarding the calibers to be tested. In pistol cartridges, thetwo most obvious contenders were the 9mm and .45. The 9mm roundtested was the 147 grain subsonic hollow point round produced byWinchester; the .45 round selected for the test was the Remington185 grain hollow point. The selection of these particularcartridges for testing was based, in large part, on the consensusof the Wound Ballistic Workshop participants that these bulletsshould provide superior penetration over other hollow pointbullets in their respective calibers.
In the meantime, a separate research and development project hadbeen undertaken with the 10mm cartridge to assess itsapplication to law enforcement work. Although the 10mm (.40caliber) is a relatively new cartridge, with few weaponspresently chambered for it, its unique position halfway in sizebetween the 9mm (.35 caliber) and the .45 appeared to offer thepossibility of a third viable law enforcement pistol cartridge. In addition, unlike its other competitors, the potential of thenew cartridge was virtually untapped.
Samples of commercially available 10mm ammunition were acquiredand preliminarily evaluated as to suitability for lawenforcement use. The high chamber pressures generated by thecommercial loadings, with the resultant heavy recoil and muzzleblast, tended to offset the otherwise excellent performance ofthe round. Therefore, the FBI Firearms Training Unit decided tocreate a new loading for the 10mm, one with velocities comparableto those of the competing 9mm and .45 cartridges. A 180 grainhollow point bullet was acquired and handloaded to a velocity of950 feet per second. This loading not only matched thevelocities of the other two cartridges, but it also dramaticallyreduced recoil and muzzle blast.
In the absence of factory ammunition built to the desiredspecifications, the 10mm rounds initially subjected to the testprotocol were those handloaded by the Firearms Training Unitstaff. Subsequently, factory⌐loaded 10mm ammunition was acquired
and built to the desired specifications, which actually met orsurpassed the performance of the handloaded test ammunition.
The Test Procedures
Because the objective was to test ammunition and not weapons, theinitial tests were conducted with industry standard test barrels. These barrels are built to standards established by the SportingArms and Ammunition Manufacturing Institute (SAAMI) and aretailored to optimize the ballistic efficiency of each caliber. Test barrel length is determined by the internal ballistics ofthe caliber. Consequently, the barrel lengths vary with eachcaliber. For example, the optimal test barrel for the 9mm is 4"in length, while those of the 10mm and .45 are 6".
The immediate concern was the possibility that the longer testbarrels for the 10mm and .45 would provide an advantage byincreasing their velocities. In reality, it was discovered thatincreased velocity actually diminishes the penetrationperformance of hollow point bullets in gelatin by increasing therate and degree of expansion. It was noted, for example, thatboth the 10mm and .45 achieved lower velocities, but greaterpenetration, when fired from shorter pistol barrels than whenfired from the longer test barrels with somewhat highervelocities. Thus, the longer test barrels used with the 10mm and.45 worked as a handicap for those two calibers by lessening thedegree of penetration. That handicap would have been eliminatedby using test barrels of equal lengths, and the disparity betweenthe penetration performance of the 9mm and the two other caliberswould have been even greater than that actually attained. Sincethe longer test barrels were not giving any advantage to the 10mmand the .45 caliber (quite the contrary), the tests werecontinued with existing equipment.
After initial tests to measure velocity and accuracy, 40 roundsof each caliber were fired by FBI firearms personnel to measurepenetration and wound volume. Following each shot, red dye wasinjected into the wound channel created by the passage of thebullet into the gelatin, and a photograph was taken. Then aseparate team from the Institutional Research and DevelopmentUnit conducted the measurements to ascertain penetration(measured in inches), bullet expansion, and retained bulletweight. Finally, the volume of tissue displaced (wound size) bythe passage of the bullet was computed in cubic inches andrecorded.
The Results
Although penetration and wound size govern handgun woundingeffectiveness, penetration is the more critical element. Therefore, a minimum standard of 12" of penetration in thegelatin was established. The following penetration resultsindicate the number and percentage of rounds in each caliber thatmet or exceeded the 12" minimum:
10mm - 39 shots out of 40 (97.5%)
.45 - 37 shots out of 40 (92.5%)
9mm - 27 shots out of 40 (67.5%)
As a point of reference, the standard issue .38 Special, 158grain lead hollowpoint round was fired through the battery oftests. Although the .38 was not a "test" round, and thereforenot fired under the same strict test controls, the penetrationperformance was similar to that of the 9mm, producing acceptablepenetration 67.5% of the time.
It should be noted that no maximum penetration standard wasestablished. This reflects the judgment that underpenetration ofa handgun bullet presents a far greater risk to the lawenforcement officer than overpenetration does to an innocentbystander. Considering that approximately 80% of the roundsfired by law enforcement officers engaged in violent encountersdo not strike the intended targets, it was deemed somewhatunrealistic to attach too much significance to the potentialrisks of overpenetration on the part of those that do. Nevertheless, in assessing the potential volume of wounds createdby the test bullets, greater attention was given to thepotential tissue displaced up to a depth of 18". For practicalpurposes, penetration beyond that range would most likely carrythe bullet outside the body.
Averaging the volumetric results over all eight test events, the10mm and .45 displaced similar volumes of tissue within thedesirable penetration range of 18"-4.11 and 4.22 cubic inchesrespectively-⌐well beyond that displaced by the 9mm and .38-¬which
respectively measured 2.82 and 2.16 cubic inches.
As an additional consideration, the 10mm was by far the mostaccurate round tested, consistently providing one hole 10⌐shotgroups at 25 yards of less than an inch (0.77" average) withboth handloaded and factory ammunition built to FBIspecifications. By contrast, the 9mm averaged 2.3" and the .45averaged 2".
CONCLUSION
The conclusion was obvious. The best performing round within theparameters of the FBI's test protocol was the 10mm. Accordingly, the Director of the FBI approved the recommendationthat the new 10mm cartridge be adopted as the standard caliberfor a new FBI pistol, and that the new pistol be procured insufficient quantities to replace existing revolvers.
The tests that led to this decision by the FBI are available, onrequest, to interested law enforcement agencies. Moreover,ammunition testing will continue, and extend to other calibersand bullets available for law enforcement use. As additional
test results are compiled, quarterly updates will be automatically
mailed to recipients of the original test report. Requests for the test report entitled "Ammunition Test Results"should be mailed to :
