SPIW: Special Purpose Individual Weapon

A Brief History of Fléchette and the SPIW Project

XM645 Fléchette

The story of fléchette goes back to World War I when the French dropped them in large quantities from aircraft on masses of ground troops. The “little arrows” were said to be able to pierce a man from head to foot. In World War II, the Germans experimented with multiple fléchette loadings in artillery shells. They also worked on larger single loadings with discarding sabots for anti-tank use.

Fast-forwarding to 1948, the seeds were sowed for the small arms use of fléchette. In June 1948, the U.S. Army’s General Staff created the civilian General Research Office to supply the Army with scientific advice on conducting operations in an age of nuclear weapons. By the end of the year, it was renamed the Operations Research Office (ORO). The ORO’s research mandate quickly spread out to conventional weapons, especially when the U.S. entered the Korean ‘police action’ in 1950. One of the first projects for the “Infantry” division of the ORO was Project ALCLAD: the development of improved body armor. The head of the division, Norman A. Hitchman, reasoned that in order to improve body armor, one had to know how wounds were created and where they were received. A mathematical analysis of three million casualty reports from both World Wars was entered into the ORO’s computers, along with on-the-spot analysis from ORO staffers in Korea. This led to the creation of Project BALANCE, a study of infantry rifle use.

To Colonel René R. Studler, U.S. Army Ordnance’s Chief of Small Arms Research and Development, this sounded as though the ORO was infringing on his turf. Between his distrust of ORO’s civilians and the increasing pressure applied by the British for adoption of a mid-range cartridge, Studler attempted to buttress his position supporting a ‘full-power’ cartridge. Studler requested that the Aberdeen Proving Grounds’ Ballistics Research Laboratory (BRL) prepare its own report on the effectiveness of the infantry combat rifle.

Both reports were finished in 1952, and the conclusions of each overlapped. In March, Donald L. Hall of BRL published “An Effectiveness Study of the Infantry Rifle.” The crux of the study was that a smaller caliber could give terminal performance equal or greater to that of a larger bore. Moreover, a smaller bore weapon might have superior hit probabilities at shorter ranges. Combined with the additional cartridges carried per unit weight, a soldier carrying the smaller caliber weapon could inflict more casualties upon the enemy than another soldier with a larger caliber weapon.

In June, the ORO published Hitchman’s report “Operational Requirements for an Infantry Hand Weapon.” Hitchman found that the majority of combat rifle use did not exceed 300 yards, and that marksmanship was severely degraded by terrain and visibility at ranges beyond 100 yards. In fact, the chance of being struck by a rifle bullet was seen as being nearly as random as being struck by a fragment from a high explosive shell. The time and amount of target exposure had more bearing on whether a target was hit versus marksmanship skills. Given such, an infantry weapon designed to provide controllable “pattern-dispersion” within a 300 yd range might be preferable to a weapon that provides precise single shots at longer distances. Furthermore, at the shorter ranges, a smaller caliber weapon might give acceptable “wounding effects” and allow for controllable “salvo or volley automatic” fire. The key to effectiveness was control; an uncontrollable automatic weapon was seen to be no more advantageous than a semi-auto counterpart. Hitchman projected that a four round salvo with a predictable 20″ spread might provide double the hit probability at 300 yards over a single shot fired from a M1 rifle. A lighter, smaller caliber cartridge would have the side benefit of allowing enough ammunition to be carried for an equivalent number of fired salvos to the individual cartridge capacity of the current rifle.

The concept of controlled “volley/burst” fire led to the creation of the multi-agency Project SALVO in November 1952. The ORO’s favored platform was a single barrel weapon using duplex or triplex loads (2 or 3 bullets in one case). Springfield Armory and Winchester created multi-barreled weapons. BRL stayed with a rather conventional entry: a modified M2 Carbine firing a .224″ caliber cartridge. The Office of Naval Research, in cooperation with Aircraft Armaments Inc. (AAI), created 12 gauge shotgun shells loaded with 32 steel fléchette. One of AAI’s founders, Irwin R. Barr had been infatuated with the fléchette concept. As early as 1951, he had been promoting single and multiple fléchette cartridges. Barr thought that the light recoil would allow for accurate burst fire, allowing hits at longer ranges. In 1954, without military funding, Barr conducted test firings of single fléchette cartridges. Encouraged by the results, Barr filed patent applications for his saboted fléchette cartridge designs. Not to be outdone by the Navy, the Army gave AAI a development contract for single fléchette cartridges in 1956. The goal was the development of rifle-fired fléchette capable of velocities of 4,000 feet per second.

In June of the same year, the first side-by-side tests of SALVO test weapons began. At the time, the only fléchette entry was AAI shotshell load. Multiple projectile loads were confirmed to have an edge in hit ratios. In further testing, the comparatively low-velocity shotgun fléchette were found to pierce one side of an issue M1 steel helmet and its liner at distances from 300 to 500 yards, and on occasion, even penetrate both sides. However, as Barr predicted, dispersion of the shotshell fléchette was erratic as the range increased. (Still, the shotshell loadings were impressive enough that the Army scaled up the concept in 1958 for the “Beehive” artillery shells. The “Beehive” shells could hold thousands of fléchette.)

In March 1957, Barr submitted his report on single fléchette cartridges to the Army. Three separate designs were created, each using a .22″ sabot with a 10 grain fléchette. The differences lay in the exact sabot attachment method. Barr claimed that a high velocity 10 grain fléchette was equally lethal as the .30 M2 rifle bullet out to 600 yards. Yet in terms of cartridge weight, five rounds of the saboted fléchette cartridge could be fired for each individual .30’06 cartridge. However, even at this early date, the issues of cartridge cost and individual accuracy were noted as potential problems. In January 1959, AAI submitted a proposal for continuing its single fléchette research. As a result, AAI received two additional Ordnance contracts for fléchette cartridge R&D. AAI submitted its first single fléchette cartridges for testing by the Infantry Board and Arctic Test Board in late 1959. While the early examples of the single fléchette cartridges were not terribly accurate compared to the issue 7.62mm NATO cartridge, they possessed greater accuracy than the duplex loads tested. Moreover, the fléchette’s trajectory was so flat that sight adjustments would not be required out to 400 yards. The Infantry Board concluded that the single fléchette cartridge had more potential than 6.35mm and 7.62mm NATO rounds for the proposed All-Purpose Hand-Held Weapon (APHHW). All of the Test Boards and CONARC recommended further development of the fléchette cartridges.

Unfortunately, AAI had yet to produce a dedicated weapon to fire their fléchette cartridges. The test platform for the 1959-60 tests was modified Winchester Model 70 rifles. In order to prove fléchette value for burst fire, AAI and Springfield Armory worked together to build multi-barreled “burst simulators.” In a 1961 BRL test, the “burst simulators” firing at 2,300 rounds per minute yielded 10% to 270% more hits than a similar length full-auto burst from a M14 rifle. In semi-auto fire, the AAI design was said to produce three times the casualties of a M14. Based on equal rounds expended, the BRL estimated that AAI’s proposed 3.5 pound APHHW could be up to seven times more effective than the M14. Another study, “Optimum Composition of the Rifle Squad and Platoon,” suggested that all members of a squad would be best armed with an AAI-style fléchette rifle (except for machinegunners). Around this time, the Ordnance Corps ordered Springfield Armory and Frankford Arsenal to begin design of alternative fléchette weapon systems and ammunition. Springfield quickly conceived two different rifle designs, along with plans for an “Universal Machine Gun” (UMG), all chambered for Frankford’s new XM144 fléchette cartridge. By the end of 1961, a contract was even awarded to Winchester to convert five of its prototype Lightweight Military Rifles (a previous competitor to the ArmaLite AR-15) to chamber the XM144.

By 1962, formal military specifications were laid down for a fléchette-firing weapon. However, Ordnance officials were not satisfied with just the point fire capabilities of a rifle; they also desired to add the area fire capability of the recently adopted M79 40mm grenade launcher. As the specification writing process drug on, the area fire capability was even expanded from single-shot to semi-automatic. This weapon’s new name would be the Special Purpose Individual Weapon (SPIW). When the final specs were issued in March 1962, it was confidently predicted that a SPIW could be type classified “Standard A” by June 1966.

However, this would be one of the last official acts by the Ordnance Corps. On 10 January 1962, Secretary of Defense Robert McNamara abolished the statutory positions of the Technical Service chiefs (such as the Chief of Ordnance), transferring them to the Secretary of the Army subject to Congressional approval of his sweeping reorganization plan for the Army. After receiving Congressional approval in February, McNamara would soon authorize the creation of the Army Materiel Command (AMC) and the Combat Developments Command (CDC). The new commands were raised to the same level as the Continental Army Command (CONARC). The responsibilities and subordinate commands of the formerly independent Technical Services (Ordnance, Chemical, Quartermaster, Transportation, and Signal Corps) were divided among the three major commands. The Technical Services lost their materiel functions to the AMC, their training functions to CONARC, and their doctrine formulation functions to the CDC. The Offices of the Chief of Ordnance and the Chemical Warfare Services were abolished, and their staff functions transferred to the office of the Army’s Deputy Chief of Staff for Logistics (DCSLOG). In August, the AMC was activated with Lt. General Frank S. Besson, Jr., the former Chief of Transportation, as its first commander. AMC was organized initially into five commodity major subordinate commands (MSCs); Electronics Command, Missile Command, Munitions Command, Mobility Command, and Weapons Command; and two functional MSCs; Supply and Maintenance Command (SMC) and Test and Evaluation Command (TECOM). Not surprisingly, Ordnance Weapons Command was the basis for the new US Army Weapons Command (USAWC or WECOM). To add insult to injury, production of the M14 rifle was halted months later and existing contracts canceled. For the holdovers from the former Ordnance Corps, the SPIW represented a last chance for glory.

In October 1962, 42 companies were briefed on the SPIW project. By December, ten companies submitted formal proposals. After a two-month study, four companies were selected. AAI and Springfield Armory were obvious choices for their pre-existing work. The other two were producers of the discontinued M14: Harrington & Richardson (H&R) and Winchester. However, this was not entirely a case of corporate Welfare. Besides its earlier contract for converted LWMR, Winchester had by this point developed their own variant of the XM144, and had also been developing a “soft recoil” mechanism under Army contract. Winchester quickly asked, and was granted permission to roll the latter project into their new work on the SPIW.

Around this point, AWC predicted that the SPIW project could be completed up to a year early (June 1965) at a cost of 21 million dollars. Both predictions would prove to be overly optimistic, as were the weapon specifications: less than 10 pounds while loaded with a minimum of three grenades and 60 fléchette cartridges. Still, the enthusiasm was infectious. In July 1963, McNamara and Secretary of the Army Cyrus Vance witnessed a demonstration of SPIW prototypes during visit to Fort Benning. McNamara expressed the hope that 1,000 SPIW could be procured and sent to South Vietnam for testing, much as the AR-15 had been the year before. McNamara’s escorts talked him out of the idea on the grounds that a large procurement of any specific prototype model would effectively prejudice the SPIW competition.

All four companies had their requested ten prototypes ready for the Phase I evaluation in March 1964. AAI continued to use its 5.6x53mm XM110 cartridge, Springfield and Winchester used Frankford’s 5.6x44mm XM144 cartridge, and H&R incorporated the XM144’s saboted projectiles into its own proprietary cartridge design. The H&R design was immediately rejected as too heavy, not to mention unsafe. H&R already had a bad reputation for its M1 and M14 rifles, not to mention its poor conversion of the FN FAL for earlier Army trials, and their new SPIW did nothing to dispel this reputation. H&R’s SPIW used David Dardick’s revolving “open chamber” concept. Each 5.6x57mm cartridge, cutely named a “tround,” was a triangular piece of plastic holding three separate sabots and fléchette with a single powder charge. Upon pulling the trigger, all three projectiles were fired at once. On the downside, each of the individual projectiles required its own barrel, adding unnecessary weight; the weapon topped 23.9 pounds loaded. More significantly, the open chamber meant that only the plastic case was available to contain the pressures of firing. Initial test shots prove that the plastic cases were not up to this task, with the walls splitting and bulging upon ignition. The testers were underwhelmed at the prospect of less than a millimeter of plastic keeping the weapon from blowing up in their face.

In April 1964, firing trials of the three remaining SPIW candidates began at Fort Benning. Winchester’s “soft recoil” SPIW rifle design was deemed too complicated. The barrel reciprocated within the stock housing (in a fashion similar to the more recent HK G11 and AN94), but the receiver length was too short to allow a three round burst to be completed prior to the action bottoming out within the receiver. The varying position of the barrel during the feed cycle was suspected as a cause of malfunctions. In contrast, Winchester’s blow-forward grenade launcher was very popular due to its relatively compact dimensions. A single trigger in conjunction with a special selector button controlled both the rifle and grenade launcher function. Given the rifle’s unreliability in later adverse condition trials, Winchester eventually dropped the rifle project. However, they continued to produce the grenade launcher under contract to Springfield Armory.

Springfield Armory’s SPIW was a bullpup design with a unique tandem magazine arrangement. A pair of 30 round magazine bodies was arranged back to back in a single assembly. The mechanism allowed the rounds of the rear magazine to be held in reserve until the forward magazine ran dry. A tab in the forward magazine’s follower then raises the rear magazine high enough to allow its rounds to feed. The designer, Richard Colby, could not get a conventional 60 round box magazine to feed reliably given the weapon’s high cyclic rate. (AAI and Winchester used drum magazines, while H&R used a taped belt.) In any case, a conventional box design would have been excessively tall, causing problems during use in prone firing positions. The Springfield SPIW passed the length restrictions, but it exceeded the weight requirement by roughly four pounds. This was in part due to their massive magazine-fed grenade launcher design.

The AAI entry was a very slick package given how crude their previous APHHW prototypes were. Their 1961 weight predictions were optimistic (by about 10 pounds), but their predicted cyclic rate was met and exceeded at 2,400 rpm. However, their grenade launcher module was not semi-automatic. Instead, AAI had settled on a less bulky lever-action mechanism.

Around this time, questions arose as to what plans the Army had to meet its need for rifles. By the summer of 1964, General Besson predicted that the type classification of the SPIW was going to be pushed back to at least January 1967. The Army’s Chief of Research & Development, Lt. General William W. Dick, Jr., estimated that the SPIW could not be fielded any sooner than the early 1970s. Even with these warnings, the Army’s General Staff briefed the Secretary of the Army that the SPIW would be ready for type classification by December 1965. Despite not having enough M14 to equip the entire active Army, the General Staff insisted that no more XM16E1 were needed or wanted, and that they would rather wait for the SPIW. If additional rifles were to be ordered, they claimed it would be preferable to restart production of the M14. General Besson, commander of the AMC, took a more pragmatic view. While the XM16E1 only offered an estimated 50% of the improvement of the SPIW over M14, at least additional quantities of the XM16E1 could be acquired long before the SPIW would ever be ready for issue.

Results of the SPIW Phase I evaluation were complete in November 1964. While the candidates were not considered to be mature enough for Phase II full-scale engineering development, certain trends were noted. The Springfield SPIW was judged to be the most reliable and accurate. AAI’s SPIW was the lightest, simplest, and considered to be most durable. Overall, none of the systems were considered to be particularly reliable or durable, and testers complained of the candidates’ weight, rapid over-heating, and excessive muzzle blast and flash. Besides the problems with test weapons, other bugs were appearing. In early production test runs, no economical way to make the fléchette cartridges was found. In order to maintain accuracy, the cartridges had to be practically hand-made. Moreover, the cartridges had problems with excessive pressure. In spite of their high penetration potential, the fléchette could be easily deflected by brush or even raindrops. Furthermore, the construction of an adequate fléchette “tracer” round was proving impossible to achieve.

Five possible approaches were discussed to continued development leading to type classification of SPIW. The current program was a 14-month accelerated development effort, with type classification scheduled for the end of the third quarter of FY 1966 (March 1966). However, this was described as an “extremely high risk alternative” and the plan least likely to result in an entirely satisfactory weapon at the time of type classification. Following this approach would have necessitated continuing the development of only the AAI version, as there would be insufficient time to exploit the advantages of the Springfield design.

The alternative courses of action called for either 20, 26, 35, or 50 month development efforts. Type classification under these alternatives would be scheduled for the first quarter of FY 1967, the third quarter of FY 1967, the second quarter of FY 1968, and the third quarter of FY 1969, respectively. WECOM recommended the 35-month development effort as the course of action which would: 1) assure satisfactory completion of the engineering and service tests; 2) provide for type classification a system with the highest reliability and fewer manufacturing start-up problems; 3) have no unsolved technical problems with the piston-primer type cartridge; and 4) provide a tracer cartridge at the time of the engineering and service tests that would meet the WECOM-proposed relaxed characteristics. The WECOM recommendation was accepted.

In March 1965, AAI and Springfield Armory were instructed to submit ten ‘second generation’ prototypes apiece for a rerunning of the Phase I evaluation process. The Army was also displeased with the unconventional layout of the designs, from the bullpup to the use of an inline stock with a pistol grip. It was decided that the next generation of SPIW should have a ‘conventional’ stock design like the M14.

In February 1966, WECOM conducted a formal “in-process review” of the SPIW program. Neither AAI nor Springfield Armory was ready to submit their second-generation SPIW prototypes. Indeed, some items had not even been designed, much less manufactured. A 90-day waiver for delivery was given as a result. In fact, neither of the second-generation SPIW candidates was ready for submission until August 1966.

The Springfield Armory candidate required significant redesign from its original bullpup configuration. While the new design still met the length restriction, it also remained overweight. The dual magazine design had been changed to a side-by-side plan constructed of clear Lexan. When one side ran dry, feed was automatically switched to the opposite side. The Winchester grenade launcher was fitted; however, it now used a preloaded, disposable magazine. One thing that proved especially difficult was the Army’s insistence that both weapons be fired from the same trigger. The complex linkages involved resulted in the grenade-trigger option having a 25-pound trigger pull.

AAI didn’t have quite as much work to convert their previous design. They designed a clever one-piece polymer buttstock/rear sight housing/magazine well. AAI’s semi-automatic grenade launcher was finally ready, and was equipped with a harmonica-style magazine. The magazine automatically ejected when empty. However, the overall weight still exceeded the project limit. AAI also proffered another grenade option, the DBCATA: Disposable Barrel and Cartridge Area Target Ammunition. The DBCATA allowed the 40mm grenade to act as its own launcher. While it would lead to a major reduction in system weight, the DBCATA was considered prohibitively expensive. Essentially, you would be throwing a barrel away after each shot.

Neither entry was terribly reliable, none achieved the weight goal, and most of the pre-existing problems were still unsolved, including the various ammunition issues. (By this point, the XM110 and XM144 had been replaced by the 5.6x57mm XM645 and 5.6x44mm XM216 cartridges.) Observers state that the blast and flash signatures even exceed those of the unmodified Colt ‘Commando’.
XM645 SPIW Cartridge

With the dismal results, Col. Yount, the Project Manager – Rifles (PMR), pushed back the SPIW’s projected type-classification to June 1968. Yet there was still significant support for the SPIW in certain quarters. In their final recommendations from the Small Arms Weapon Systems (SAWS) trials, the Army’s Combat Developments Command Infantry Agency wanted to cap current orders of the XM16E1 until the SPIW was ready. Development of the SPIW and UMG were to be continued with hopes of fielding them by 1970 and 1972 respectively. Mind you, while the 5.56mm and 7.62mm weapons in the SAWS trials were tested in live fire experiments, the testing of the fléchette weapons was conducted solely by computer simulations. In September 1966, the Deputy Chief Staff of the Army for Logistics (DCSLOG) published the 1966 Army Materiel Plan, which included the implication that the SPIW had been selected as the successor system to the M14.

With Springfield Armory scheduled for closure in less than two years, WECOM suddenly came to the realization that soon no one would be left to compete with AAI for the SPIW contract. In October 1966, industry representatives were invited to Fort Benning to witness SPIW testing in hopes of someone picking up the Springfield design. One of the representatives was Colt’s Engineering Project Manager, Robert Roy. Needless to say, Colt was curious to see what was competing against their M16 rifle; they had even gone to the extent of creating a 5.56x45mm fléchette load with a companion smoothbore M16. Upon witnessing the tests, Roy reported to his superiors that there was no reason to save the Springfield SPIW, as the program was unlikely to be debugged anytime soon. Moreover, such efforts would only serve take attention away from Colt’s own M16.

Others fell to the same conclusion. The Army’s new systems analysis group, the Force Planning and Analysis Office (FPAO) had recommended that the SPIW be reoriented to a long-range research program, current procurement should center on the XM16E1 and the M60, with the possible adoption of the Stoner 63 to fill the Automatic Rifle role. The Infantry Board also recommended that the SPIW program be cut back, with greater responsibility given to AAI to develop a working model. In November 1966, the Army’s Chief of Staff, General Harold K. Johnson, announced his recommendations that the SPIW be reoriented to the status of exploratory development, and that the XM16E1 rifle be adopted for all operational theatres except Europe. (By then, the Army had nearly run out of M14 rifles, and was faced with the prospect of issuing M1 rifles to combat troops going to Vietnam.)

To support a future reactivation of the program, AAI was awarded a “nominal fee” contract in February 1967 to continue improvements of their SPIW candidate. Two of the second-generation SPIW prototypes were returned to AAI for further modification and experimentation. By September 1967, AAI began to make real progress in extending functional reliability. However, during in-house trials, the pre-existing issue of rapid heating turned into actual occurrences of cartridge cook-offs. Ironically, the prototypes had never managed to function long enough to experience this problem in the past. By November, AAI initiated a second set of in-house trials now concentrating on eliminating the cook-off problem.

In the mean time, SPIW advocates in the BRL and other Army agencies refused to let the project fade away, issuing favorable reports on the potential gains in hit percentages. AAI finally had a major sales success in the M203 40mm grenade launcher in 1968; this along with continued subsidies from the Army allowed AAI to continue developing their SPIW prototypes. This persistence paid off in 1969 when WECOM awarded AAI a contract for the XM19 rifle, under the Future Rifle Program (FRP). Moreover, General Electric was coaxed into continuing development of the orphaned Springfield Armory SPIW. Moreover, work had begun on single cartridge/multiple fléchette loadings. Beside the work on Serial Fléchette Rifles (SFR: the new name for SPIW rifles), alternate development projects had begun of single cartridge/multiple fléchette loadings (by Olin-Winchester), micro-caliber Serial Bullet Rifles (SBR), and caseless cartridges.

Unfortunately, the FRP/SFR project soon came under investigation by the U.S. Congress and the General Accounting Office (GAO). The attacks centered on the seeming lack of progress for the $20+ million already invested in SPIW-type weapons. (Note: The SPIW program eventually spent roughly six times the amount of money which had been used to the develop the M14 rifle.) Matters were not helped when the Army amended the accuracy requirements of the SPIW/SFR’s Materiel Needs Statement. With the requirements changed from a mean burst pattern to a single shot, the existing fléchette cartridges no longer met the accuracy standards. Worse yet, a number of soldiers involved in XM19 test-firings began to complain of various aliments, with the reports even reaching as high as the Army’s Surgeon General of various aliments. These issues included severe nausea, inflammations, and even eye injuries, all apparently caused by particles from the fiberglass sabot of the fléchette cartridges. Around the same timeframe, Colt’s Technik, Inc. published “Feasibility Study of Fléchette Fired from Rifled Barrel.” In experiments conducted on behalf of Frankford Arsenal, saboted fléchette have been loaded into standard 5.56x45mm cases and fired through M16 rifles. Conceived as a low-cost way of testing different sabot/fléchette designs, the improved accuracy results cast doubt upon the existing SFR weapon and cartridge designs.

Despite these setbacks, the SPIW/SFR program limped along with AAI receiving an additional contract in 1972 for a stripped-down XM19 variant, to be known as the XM70. During the course of XM70 development, Picatinny Arsenal designed an experimental 30mm grenade cartridge, in hopes of reducing system weight over the current-issue 40x46mm grenades. However, it had become a matter of “too little, too late.” In December 1973, fléchette ammunition had been removed altogether from “immediate consideration” in the Future Rifle System (FRS) Program. (AAI did not submit their XM70 SFR prototype for testing until May 1974.) Instead, efforts were reoriented toward the micro-caliber SBR.

Adding insult to injury, in October 1974, the Human Engineering Labs at Aberdeen pitted the sole AAI XM70 SFR prototype against a pair of Frankford’s early experimental 4.32x45mm XM16E1 SBR. The XM70 ceased to function after a mere six bursts. While AAI received later contracts for their own SBR, the micro-caliber rifles created their own problems with excessive fouling, over-heating, and inadequate bullet integrity in flight. Moreover, none of the SBR was found to be as controllable as the earlier SFR candidates, even with the use of experimental muzzle brakes.

While the SPIW/SFR projects were effectively dead, AAI never really gave up on the concept. In June 1978, AAI published the document “Proposal for the Development of Improved Small Arms Fléchette Ammunition.” During the Close Assault Weapon System (CAWS) program of the early/mid-’80s, AAI’s special 12 Gauge cartridge launched eight large fléchette, each reportedly weighing close to 31 grains, at nearly 1950 fps. Olin, in support of HK’s CAW, also offered a fléchette load, using twenty much smaller projectiles at a much higher velocity (~2,950 fps).

The later Advanced Combat Rifle (ACR) program brought out even more fléchette candidates. AAI’s ACR entry harkened back to their ’70s-era SBR. However, instead firing micro-caliber cartridges formed from a 5.56x45mm parent case, AAI loaded the standard 5.56x45mm case with a saboted fléchette. Unfortunately, while the AAI ACR’s magazine was specially sized to prevent insertion of standard 5.56mm NATO cartridges, a standard cartridge could still be manually chambered in the rifle. Combined with the fléchette-tuned gas system, such a mix-up could result in a very serious mishap (kaBOOM!). As with earlier AAI fléchette rifles, users complained of the high noise levels. However, the addition of a sound moderator/muzzle brake brought the muzzle blast down nearly to the level of a standard M16A2.

Steyr’s ACR outwardly resembled their flagship AUG family; however, the internal mechanism of their ACR was quite radical. Nearly the entire design, from the “raising chamber” mechanism to the completely cylindrical, synthetic-cased fléchette (SCF) cartridge, was credited to Ulrich Zedrosser. Upon firing, the chamber would slide down and a separate piston would strip a new cartridge from the magazine into the chamber. As the new cartridge entered the chamber from the rear, it pushed the fired case forward out of the chamber to eject it. Then the chamber would rise in line with the barrel for firing. The extremely high chamber pressures quoted for the system (60,000 to 70,000 psi) caused some concerns; however, there is no hard data to indicate that any real problems developed. While the light fléchette/sabot combination allowed the very high cyclic rate to remain controllable, both Steyr and AAI limited their designs to three round bursts.

McDonnell Douglas Helicopter Company (MDHC) was slated to enter a third fléchette-firing ACR prototype; however, it reportedly rejected for “technical issues.” L. James Sullivan was responsible for the weapon’s design, based on Hughes’ ’70s-era “Lockless” weapon and cartridge system. (McDonnell Douglas had earlier bought out Hughes’ helicopter and armament interests, which now comprised the MDHC division.) Evoking comparisons to H&R‘s 1962 SPIW entry, the MDHC Advanced Individual Weapon System (AIWS) used a plastic-cased, multiple fléchette cartridge. However, unlike the triangular Dardick Tround, the “Lockless” cartridge was described as a “chiclet,” due to its flat, rectangular box profile. The saboted fléchette were set in the center of the box, surrounded on either side by compartments filed with propellant. The weapon’s barrel was closed off at the breech end, and the chiclets are fed into the chamber through a slot through the bottom of the barrel. A pressure sleeve is then closed over the open chamber’s sides before the round is fired. The spent case is then pushed out through the top of the barrel by the next cartridge as it slides into the chamber. The drawback of this system is that the amount of propellant needed is quite high, in this case nearly 3.5 times that of the 5.56mm NATO. Initial work involved duplex and triplex loadings of conventional projectiles, but due to high recoil, this was scaled back to multiplex fléchette loadings. This started with a .42 caliber five fléchette load, and was eventually whittled back to four and then three fléchette loaded in a .338 caliber sabot.

Although most of the ACR trial results are still either classified or limited distribution, it is known that the AAI and Steyr fléchette cartridges were considered to be less accurate than their conventional projectile rivals. However, none of the ACR candidates were considered to offer a large enough hit probability over the standard M16A2 to warrant further development or adoption.

Today, the serial fléchette rifle concept remains dormant, although canister cartridges using large numbers of fléchette are still under development for other weapon systems. The SPIW program’s concept of combining point and area target capabilities in a single infantry weapon lives on in the current Objective Infantry Combat Weapon (OICW) program. Ironically, one of the major hurdles which hamstrung the SPIW, overall system weight, continues to haunt the current OICW candidate, Alliant Techsystems’ XM29. As a result, the OICW was changed to a spiral development program. The rifle and grenade launcher’s development are to progress independently until such time as their weight can be reduced to a point whether the individual items can be recombined. This leaves the user of the grenade launcher, the XM25, with a problem as to how to engage close-in targets. The solution currently proposed is a multiple fléchette cartridge.

(To be continued…)

by Daniel E. Watters, Small Arms Historian
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Document History
Publication: 05/12/2003
Last Revised: 10/03/2008

Author’s Note
This article was originally published at The Gun Zone — The Gunperson’s Authoritative Internet Information Resource. My friend and mentor Dean Speir has graciously hosted my articles at TGZ for nearly 16 years. These articles would likely have never appeared online without his constant encouragement and assistance.

With TGZ’s closure in early 2017, Dean encouraged me to find a new home for my scholarship so it wouldn’t be lost in the dustbin of the Internet. Loose Rounds has welcomed me with open arms. In the future, I intend to expand my legacy TGZ articles and add new contributions here at Loose Rounds.


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