Springfield Armory Museum - Collection Record
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|Title:||RIFLE, ASSAULT - U.S. ASSAULT RIFLE SPIW SN# 4|
|Date of Manufacture:|
|Catalog Number:||SPAR 3162|
U.S. ASSAULT RIFLE SPIW XM110 SN# 4
Manufactured by Aircraft Armaments, Inc., Baltimore, Md.
HISTORICAL SUMMARY OF ACTIVITIES:
1JAN61 - 30JUN61 - "The development by Aircraft Armaments, Inc. of mechanisms to fire the XM110 ammunition continued. This work was directed toward increased overall mechanism reliability, improvement of the burst/rate control mechanism, and development of a high capacity magazine and associated feeding system."
Notes: "Special Purpose Individual Weapons: A Brief History of Fléchette and the SPIW Project.
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 are sowed for the small arms use of fléchette. In September 1948, the U.S. Army's General Staff creates the civilian Operations Research Office (ORO) to supply the Army with scientific advice on conducting operations in an age of nuclear weapons. 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. To Colonel René R. Studler, US Army Ordnance's Chief of Small Arms Research and Development, this sounds as though the ORO is 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 attempts to buttress his position supporting a 'full-power' cartridge. Studler requests 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 is control; an uncontrollable automatic weapon is 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 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. Even before the SALVO tests, he had been developing single and multiple fléchette cartridges without military funding. Barr thought that the light recoil would allow for accurate burst fire, allowing hits at longer ranges. Not to be outdone by the Navy, the Army gave AAI a development contract in May 1956. In June of the same year, the first side-by-side tests of SALVO test weapons began. Multiple projectile loads were found to have an edge in hit ratios. In further testing in 1957, the shotgun fléchette loads were found to pierce one side of an issue M1 steel helmet and its liner at distances from 300 to 500 yards. 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.)
AAI was ready to submit its first single fléchette cartridges for testing by the Infantry Board and Arctic Test board in 1960. While the early examples were not terribly accurate compared to the issue 7.62x51mm 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. Unfortunately, AAI had yet to produce a dedicated weapon to fire their fléchette cartridges. The test platform for the 1960 tests were modified Winchester Model 70 test 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 2300 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 was said to produce three times the casualties of a M14. AAI predicted that they would be able to create a rifle with the same characteristics that weighed only 3.5 pounds. After 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), the Ordnance Corps ordered Springfield Armory to start its own fléchette weapon system.
In 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 (the ORO's Project NIBLICK). As the specification writing process drug on, the area fire capability was 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 was one of the last official acts by the Ordnance Corps. On 1 July 1962, Secretary of Defense Robert McNamara merged the Ordnance, Chemical, Quartermaster, Transportation, and Signal Corps into the new Army Material Command. Ordnance was reduced significantly in to injury, production of the M14 rifle was halted and existing contracts canceled. For the holdovers from Ordnance, 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 contracts were awarded: AAI and Springfield Armory were obvious choices, and the other two were former producers of the M14, Harrington & Richardson (H&R) and Winchester. Around this point AWC predicted that the SPIW project could be completed up to a year early 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, 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 a new 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 the 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, firing trials of the three remaining SPIW candidates began at Fort Benning. Winchester's "soft recoil" SPIW rifle design was deemed too complicated. The barreled action 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. 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 controls 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 were 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 Results of the SPIW Phase I evaluation were complete in November. 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.
In March 1965, WECOM revised the SPIW development plan, now scheduled to span 35 months. AAI and Springfield Armory are 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 were 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 were 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 achieve the weight goal, and the most of the pre-existing problems are 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'.
With Springfield Armory scheduled for closure in lesfor 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. 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. publishes "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 designsDespite 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 towards 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 were 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 1950fps. Olin, in support of HK's CAW, also offered a fléchette load, using twenty much smaller projectiles at a much higher velocity (~2950fps).
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 70,000psi) 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 sed 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 Techsystem's XM29." - http://www.thegunzone.com/556dw-5.html
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