AAI Advanced Combat Rifle

[Uninen]

AAI Advanced Combat Rifle

The American search for an Advanced Combat Rifle (ACR) began in the early 1980s with the decision to seek new rifle design for adoption in about 1995. Multi-million-dollar contracts were awarded to a number of companies to develop caseless rifles, and later, futher contracts to other companies to examine non-caseless solutions. The designers were given free hand within broad limits of weight and size, the primary stipulation being that the rifle had to give 100 percent improvement in first round hit probability over current M16A1 rifle.

Eventually, in 1989, four candidate weapons were tested, from Heckler & Koch of Germany, Colt and AAi Corporation of the USA and the Steyr-Mannlicher of Austria. Testing was prolonged and expensive, and at the end of it the US Army decided that while all the candidate rifles showed merit, none provided the quantum leap in performance that was desired. The program was placed on hold in 1990, and that was that. However, the various designs are worth of study, because they suggest the way that the next generation of rifles might go, as and when the armies of the world show suffient interest.

The AAI rifle, compared to some of the others, looks quite conventional, but it actually fires fin-stabilized Flechettes, dart-like projectiles, at the high velocity of 1400 m/s and cannot fire conventional ammunition. The rifle is driven by gas piston, and although full details of the breech mechanism have not been revealed, it is said to be derived from earlier AAI design which, in its most efficient form, used three-chambered breech unit which moved very quickly in and out of engagement with the barrel to allow very fast cycling of a three-round burst. There is no provision for full automatic fire.

A four-power sight is fitted (ACOG), with iron sights as backup, and teh muzzle carries a rather unusual compensator / muzzle brake which has been especially designed to work with Flechettes.

The Barrel is rifled with very slow twist - one turn in 85 inches - which gives the Flechette a degree of roll stabilization and helps accuracy. The Flechette idea is not new, several makers, including AAI, experimented with Flechettes as rifle projectiles in the 1960s, but at the time the materials and construction of the Flechette cartridge was not particularly good. By now new materials and improved technology has made the Flechette concept more acceptable, and the AAI rifle was considered a good design, although not sufficiently accurate for purpose intended.

--

http://personal.inet.fi/koti/uninen/uploads/Rf/aai1.jpg
AAI Advanced Combat Rifle, with early "ACOG" sight.

http://personal.inet.fi/koti/uninen/uploads/Rf/AAI.JPG
AAI Advanced Combat Rifle

--

Manufacturer AAI Corporation, Baltimore, MD, USA
Type Gas-operated, semi-automatic nad three-round bursts
Calibre 5.56 Special
Barrel 525mm
Weight 3.53kg
Magazine Capacity 30 rounds.

--

More pics?

Anybody?

Remov?

:)

[Operation Ivy]

hmmm never herd of it, very interesting, kinda ugly though :D

Baltimore, MD, USA
woot

[Tony Williams]

If adopted, the problem may have been with the effectiveness of that flechette loading. This is from 'Assault Rifle: the Development of the Modern Military Rifle and its Ammunition' by Max Popenker and myself:

"It is often believed that 'hydrostatic shock' caused by the high velocity impact of a bullet has a significant disabling effect on the victim. However, this is disputed by others, who state that the damage caused by the wound channel is the only cause of injury. It is undoubtedly true, as demonstrated by recent experience in Iraq, that people can be shot at point blank range by high-velocity rifle bullets yet still carry on fighting, clearly not disabled by shock. Some tests indicate that people hit by bullets or fragments travelling in excess of the speed of sound in flesh (around 1,500 m/s or 4,900 fps) suffer far more serious injuries because of the shock wave travelling through their bodies, although this is disputed by others. This could become a significant issue if flechettes were to be reconsidered, as they remain stable in flesh and create extremely narrow wound channels; without some added wounding mechanism, they are likely to prove ineffective. One flechette design, for the Winchester XM258 shotgun round, had an annular groove around the middle to encourage it to break in two on impact, but it is not known how effective that would be."

Tony Williams: Military gun and ammunition website (http://www.quarry.nildram.co.uk) and Discussion forum (http://forums.delphiforums.com/autogun/messages/)

[Uninen]

Ivy,

The weapon is actually quite nice looking.. its just those pics that i found in the net that are just horrible and "twisted" etc..

I have few good ones in a book.. but again, no scanner..

:|

[Uninen]

And anyhow, i was under the illusion that Flechettes had actually already proved their usefulness and lethality in Nam..

Guess i was wrong..

Or was i?

[cavtroop4]

those flechettes your mentioning was used on the m-79, 40mm rounds and still used today on the m-203's. clears bunkers and other enclosed spaces really well. other than that isn't the military trying the xm systems?

[Uninen]

Yeah,

40mm round was ONE of those, they also used Flechettes in shotguns and on some rifle in Nam, even had a MG that fired Flechettes only..

Also 70mm FFAR or "Hyrdra" rockets had Flechette payloads.. and 105mm arty shells..

:)

I think that the Nam really was a happy time for Flechettes in US military..

;)

Btw, the COLTS ACR (still very much like M16 series..) mentioned in my orginal text, it was more conventional rifle using "DUPLEX" 5,56 ammo.. "DUPLEX" also a thing that first saw (combat) use in Nam..

Duplex = 2 bullets in one "round"

[BeMBeN]

i found something interesting at crye associates page

a modular caseless carbine for us army
http://cryeassociates.com/work/12.htm

[Bacilluspolymyxa]

http://www.wapahani.com/rifles.html
http://www.thegunzone.com/spiw.html[/img]

[Claymore]

i found something interesting at crye associates page

a modular caseless carbine for us army
http://cryeassociates.com/work/12.htm


"The carbine used in that article was a prop (for obvious safety reasons). It was made by Crye Associates as a futuristic looking weapon for the Future Force Warrior program and to highlight their MultiCam which was then in contention for the Army's new uniform"

[Firefly26]

Makes me remember when I first discovered the Steyr ACR from "The Punisher: Armory" when I was in like 7th grade. It still sounds really good for sniping since its flat trajectory. But I'm probably talking out of my arse.

http://world.guns.ru/assault/steyr_acr.jpg

Caliber: 5.6 mm fleschette
Action: Gas operated, rising breech
Overall length: mm
Barrel length: 540 mm
Weigth: 3.23 kg w/o magazine
Rate of fire: rounds per minute
Magazine capacity: 24 rounds


The Advanced Combat Rifle program was started by the US Army in the late 1980s with the main goal to improve the hit probability of average infantry soldier by at least 100 percents above the M16A2 capabilities. During this trials, held in the early 1990s, some new and existing designs from several companies were tested, with more or less sucess, but no one achieved the 100% improvement in hit probablility over the existing M16 rifle, so program was terminated and all participating designs were freezed, which is pity. One of the most interesting participants was a design of the austrian company Steyr-Mannlicher AG.

The Steyr ACR was built as an attempt to revive the fleschette ammunition concept, first tried in the 1960s during US Army SPIW program. In 1960s, the fleschette concept was a failure. In 1990s, it was much more sucessful, but not enough to be worth of total rearming to the new infantry weapon system.

Steyr ACR is built around a specially designed cartridge of nominal caliber of 5.56mm. This cartridge has simple, cylindrically shaped plastic case. The fleschette, or dart, is totally enclosed in the case. Fleschette diameter is about 1.5 mm (.06 inch), lenght is about 41 mm (1.6 inch), weight 0.66 gramm (10 grains). Fleschette is partially enclosed into discarding sabot, and leaves the muzzle at impressive velocity of 1450 meters per second (4750 fps), still retaining velocity of 910 m/s (2980 fps) at the range of 600 meters. The plastic case had no rim or extracting groove, and priming compound is located annually at the inside wall of the case.

To fire such uncommon cartridge, Steyr ACR has equally uncommon design. Barrel of nominal caliber of 5.56mm, has a very slow rifling to give initial stabilisation to the fleschette, which is stabilised in flight by its own small fins. Instead of common linear-moving bolt, Steyr ACR have separate chamber (breech block), which can be moved up and down. The whole action is powered by gas drive, which has annual gas piston, located around the barrel. To understand this system i will explain how it works:
at first, lets suppose that chamber is empty and rifle is manually cocked for the first shot. In this position the chamber block is its lowest position, aligned with the topmost round in magazine. The gas piston with its operating rod is in its rearmost position and under the pressure of the return spring. When trigger is pressed, the operating rod with gas piston are released and started forward under the pressure of the return spring, which is located around the barrel. This movement, at first, via special rammer, feeds the first round forward from magazine and into the chamber, and then, via shaped cam and breech block spring, rises the breech block with the cartridge into the topmost position. In this position the fixed firing pin passes through the hole in the top of the chamber and penetrates the cartridge wall, igniting the primer composition and firing the round. When projectile (fleschette with sabot) passes the gas port, some of powder gases began to move the gas piston back. This movement, via the operating rod and shaped cam, loweres the breech block with empty case out of alignment with barrel and down to the magazine. When breech comes to stop in the lowest position, a separate rammer feeds next cartridge forward and out of magazine, chambering it. At the same time, the fired case is pushed forward out of the chamber by the next cartridge, and when cleared from the chamber, the spent case simply falls down out of the rifle via the ejection port. The ejection port is located at the bottom of the rifle, ahead of magazine, and this eliminates one of the biggest problems of any bull-pup rifle - a non-ambidextrous (or, in this case - fully ambidextrous) ejection.

If rifle is set to the full auto mode, the firing cycle is repeated as descibed above. Otherwise, the loaded breech remains in its lowest position, awaiting for the next trigger pull.

This quite comprehensive action was concealed in sleek and comfortable polymer case with AUG-styled pistol grip and large ventilated upper rib with fixed sights. Optical sights also were fitted. Due to extremely high projectile velocity, flight time was very short at any practical ranges, and trajectory was wery flat, giving the shooter almost ray-gun performance, which allowed to fire withouth prior calculations of point of impact - speaking simply, at any practical combat ranges shooter will hit where it aimed, regardless target movements (projectile flight time to the target at 300 meters is about 0.2 seconds). Due to high velocity, Steyr ACR had good killing power and armour piercing capablities, and due to the low weight of the projectile recoil was low. But it was not enough to double the M16 performance, so, for now, the Steyr ACR remains in prototype or preproductional state and the program is freezed if not abandoned at all.


http://world.guns.ru/assault/as56-e.htm

http://www.army.lt/guns/auto/aus2_03.jpg

[TacoDelRio]

Uninen is back?

oh ****....

[MolliG]

Uninen is back?

oh ****....

Take a look at the dates. ;)

[TacoDelRio]

Oops. Got me scared for a minute there!

[SMGLee]

ACRs located at Knights Armament.

http://photos.imageevent.com/smglee/kactour/KACTour135.jpg

ACR was a failure, one of the biggest improvement to US military markmanship is gthe addition of gthe forward vertical grip.

OCIW is the child of the ACR project, and what actually came of of it is the current XM8.

[Hakkapeliitta]

"DUPLEX" also a thing that first saw (combat) use in Nam..

Duplex = 2 bullets in one "round"

Yes, US Navy riverboats used so called SSB (Salvo Squeeze Bore) rounds in their .50 cal machineguns in Vietnam. Ask Kerry. ;)
An SSB round has FIVE zincplated steelbullets in one case. Outcome: five holes in "Charlie" instead of one.

[Hakkapeliitta]

Double post.

[rob]

but that means five smaller holes in charlie instead of one really big one. :P

[BlitZ933]

I wonder if that'd actually be effective or not? A .50 cal bullet is almost a guaranteed kill if you get a body hit, and it's fully capable of riping limbs off if it gets good contact with one. I wonder how effective the smaller rounds actually are? All I can figure is it was used to hosing down an area, meant more probable hits when you couldn't see the target, just the general spot where the fire was coming from?

[Hakkapeliitta]

I wonder if that'd actually be effective or not? A .50 cal bullet is almost a guaranteed kill if you get a body hit, and it's fully capable of riping limbs off if it gets good contact with one. I wonder how effective the smaller rounds actually are? All I can figure is it was used to hosing down an area, meant more probable hits when you couldn't see the target, just the general spot where the fire was coming from?

And I bet the SSB bullets were quite inaccurate too. Turning a machinegun into a shotgun does sound slightly illogical, but maybe it was practical when firing from a moving boat.

[Durandal]

My uncle worked at AAI after he retired in the early 80s. He worked on their CAWS system.

Here is some information on both systems and AAI's competition (and failures) with other companies like Colt.

Special Purpose Individual Weapons
A Brief History of Fléchette and the SPIW Project
by Daniel E. Watters, Small Arms Historian

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 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. 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 stature and renamed the U.S. Army Weapons Command (AWC). To add insult 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 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 2400 rpm. However, their grenade launcher module was not semi-automatic. Instead, AAI had settled on a less bulky level-action mechanism.

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 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. In November 1966, the Army came to the same conclusion, putting the SPIW on the back-burner and announcing the official adoption of the M16 rifle 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. 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 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 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 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 Techsystem's XM29.


Or go here.

[D.E. Watters]

It would have been much easier to link to the original article. The author has other interesting articles there.

http://www.thegunzone.com/spiw.html

[Durandal]

It would have been much easier to link to the original article. The author has other interesting articles there.

http://www.thegunzone.com/spiw.html

Woops, I meant to link it.

I always post both. *shrug*