The 5.56 X 45mm “Timeline” – 1989

A Chronology of Development by Daniel E. Watters



BAe/RO purchases Sterling Armament and then closes its facilities soon afterwards.

The British hold additional Environmental User Trials for the SA80. As before, two different modification packages for the IW/LSW are tested. These are known as the XL85E3/XL86E3 and the XL86E4/XL86E4. Parts modified for the E3 and E4 include the following:

  • Bolt
  • Ejector spring
  • Magazine housing insert
  • Interceptor sear
  • Pistol grip (E3 only)
  • Trigger
  • Take-down pins
  • Safety plunger (E3: Plastic; E4: Aluminum)
  • Safety plunger spring
  • Trigger return spring
  • Butt plate assembly
  • Cam stud rail
  • Ejection port dust cover
  • Dust cover spring
  • Flash suppressor
  • Cheek pad
  • Recoil rod assembly and springs
  • Gas piston
  • Piston spring
  • Gas plug
  • Cocking handle
  • Handguards
  • Receiver extension (LSW)
  • Bipod (LSW)

The Australian Engineering Development Establishment (EDE) conducts, on behalf of the Small Arms Replacement Project (SARP), an evaluation of the FN Minimi LMG to ascertain its level of acceptance into Australian service.

Japan adopts the Howa Type 89.

FFV begins deliveries of the Ak5B, a designated marksman version of the basic Ak5. It is equipped with a British SUSAT optic.

SIG introduces the SG550 Sniper.

Approximately 7,500 Wieger rifles and 1,800,000 rounds of 5.56mm ammunition are shipped to India.

The Czechs begin field testing of the 5.45mm LADA rifle.

GIAT offers to provide the TDP for its 5.7x22mm PDW cartridge to other designers and companies.

The Peruvian Army awards a $7,867,550 contract for the delivery of 10,000 Wieger STG942 and 10,000,000 rounds of 5.56mm ammunition.

The GAO denies Colt’s protest over FNMI‘s M16A2 contract award.

AMCCOM awards a $25,493,000 contract modification to FNMI for the M16A2.

AMCCOM awards a $291,000 contract modification to Colt for ACR RDT&E.

Colt tests ELCAN’s final design for the ACR optic.

Diemaco achieves the goal of 100 percent Canadian production for the C7.

The British ITDU starts SA80 Cold/Dry Environmental Trials in Norway.

Beta Co. receives a L85A1 and L86A1 on loan from the British MOD for testing with the C-Mag.

FN‘s Rene Predazzer files an US patent application for the design of the P90’s horizontally-mounted magazine.

AMCCOM awards $222,000 and $58,000 delivery orders to Colt related to the M16 for FMS.

Colt completes assembly of the first six Phase III ACR prototypes.

AMCCOM awards a $728,000 contract modification to Steyr for ACR RDT&E.

The British ITDU ends SA80 Cold/Dry Environmental Trials in Norway.

Brunswick completes NDI qualification of the RAW.

Colt submits their Phase III ACR prototypes to Aberdeen.

Colt’s Paul G. Kennedy files a patent application for the ACR‘s handguard design.

AMCCOM awards a $198,000 delivery order to Colt related to the M16 for FMS.

HK delivers the first five ACR, along with 6,000 rounds of ammunition.

The Canadian military announces that they are adopting ARMS, Inc.’s proposed dovetail dimensions for their flat-top C7 project.

The Australian EDE finds that significant reductions in the dispersion size of 5-round bursts with the FN Minimi are achieved when the original Minimi flash suppressor is replaced with a flash suppressor from either the F88 rifle or a MAG58 GPMG.

The five submitted ACR designs are narrowed to four by Aberdeen’s Combat Systems Test Agency. The remaining four candidates are then cleared for the 9 month field experiments at Fort Benning. Colt’s ACR is most the conservative, being merely a flattop M16-variant with an improved hydraulic buffer, a more ergonomic collapsible stock, and the muzzle brake/compensator/flash hider assembly designed by Reed Knight. The oddest addition is the forearm, featuring a tall sighting rib inspired by the earlier HEL tests. The Colt ACR is submitted with an Olin-designed duplex 5.56mm load. The two projectiles weighed 35 grains (front) and 33 grains (rear), giving a velocity of ~2900 fps. The rifle retains the ability to use the issue M855 cartridge.

HK‘s ACR is yet another variant of their G11 caseless rifle. Most will note the change in cartridge nomenclature: 4.92x34mm versus 4.73x33mm. However, this is merely a matter of semantics; the projectile size remains the same (0.194″).

AAI’s ACR entry harkens back to their 1970s-era SBR. However, instead firing micro-caliber cartridges formed from a 5.56x45mm parent case, AAI loads a standard 5.56x45mm case with a saboted fléchette (similar in principle to Frankford Arsenal’s earlier experiments). Unfortunately, while the AAI ACR‘s magazine is 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. (As Dean would say: kaBOOM!) As with earlier AAI fléchette rifles, users complain of the high noise levels. However, the addition of a sound moderator/muzzle brake brings the muzzle blast down nearly to the level of a standard M16A2.

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

ARES fails to perfect their own belt-fed, bullpup ACR design in time, and withdraws their entry. Designed by Gene Stoner and developed by Francis Warin, the ARES Advanced Individual Weapon System (AIWS) fires a conventional 5mm tracer projectile (weighing 45 grains) from a synthetic cased cartridge, using a raising chamber design similar to the Steyr ACR.

AMCCOM awards a $376,000 contract modification to AAI for ACR RDT&E.

Steyr’s Ulrich Zedrosser receives US Patent #4,817,496 titled “Firearm.”

British armorers receive a modified magazine catch for retrofit to the SA80. The new magazine catches have a reduced profile to prevent the accidental release of the magazine.

The Brazilian Army issues a Experimental Technical Report clearing the way for series manufacture of the IMBEL MD1 rifle.

NATO publishes document D/296, outlining a new requirement for a Personal Defense Weapon (PDW).

Phrobis III’s Charles A. Finn receives US Patent #4,821,356 titled “Military Bayonet and Scabbard.”

Colt conducts final test firing of their Phase III ACR prototypes. The final fifteen rifles are then submitted for the ACR field trials.

AMCCOM awards a $3,761,000 delivery order to FN related to the M249.

The British ITDU conducts SA80 Hot/Dry Environmental Trials.

Steyr’s Ulrich Zedrosser files an US patent application for the annular primer design used by the Steyr ACR‘s SCF cartridge.

Peru receives a shipment of 2,000 Wieger STG942 and 2,000,000 rounds of 5.56mm ammunition. No further deliveries are made after the collapse of the East German government.

The ITDU also ends testing of the “Low Tech Sound Suppressor” from List Precision Engineering.

AMCCOM awards a $1,840,000 contract modification to Colt related to the 1967 Licensing Agreement.

The AMSAA publishes “Independent Evaluation Plan (IEP) for the Advanced Combat Rifle.”

AMCCOM awards a $238,000 contract modification to AAI for ACR RDT&E.

The British ITDU conducts SA80 Hot/Wet Environmental Trials in Brunei.

The ITDU also tests a one-piece sling for the SA80.

Olin’s Stephen J. Bilsbury, William G. Dennis, Jr., and Stephen K. Kernosky file a patent application for a low-cost method of fabricating the M855’s steel penetrator.

Colt begins training the military trainers assigned to the ACR field tests.

AMCCOM awards a $386,000 contract modification to Colt for ACR RDT&E.

AMCCOM awards a $117,000 contract modification to ARES for ACR RDT&E.

ARDEC releases “Molding of Fiber Glass/Epoxy Handguards for the SFLM (Serial Flechétte Launch Mechanism) Advanced Combat Rifle.”

The Australian EDE publishes “Australian MINIMI F89 Light Support Weapon (LSW)/Plash Suppressor Test Report.”

The Indian Army asks the Ordnance Board to accelerate development of the INSAS family in hopes of service introduction as early as 1990.

Steyr’s Ulrich Zedrosser receives US Patent #4,846,068 titled “Cartridge for Firearms” and US Patent #4,848,237 titled “Peripheral Primer Firearm Cartridge.”

AMCCOM awards a $25,000 delivery order to FN related to the M249.

Richard Swan of ARMS, Inc. is shipped a sample of the Colt ACR‘s upper receiver and forging along with a purchase order for reengineering the upper receiver’s scope rail. One of the main goals is to increase the strength the rail, as the existing rails cuts make the receiver too thin. (Reportedly, Swan demonstrated to Colt’s Robert Roy that he could pierce the receiver at the bottom of the cut using the point of a Number 2 pencil.)

AMCCOM awards a $216,000 contract modification to Colt for ACR RDT&E.

AMCCOM awards a $163,000 contract modification to Steyr for ACR RDT&E.

AMCCOM awards a $50,000 contract modification to AAI for ACR RDT&E.

AMCCOM awards a $260,000 contract modification to MDHC for ACR RDT&E.

Special Operations Special Technology (SOST) Modular Close Combat Carbine Project is funded. (This is the forerunner to the terminology “Special Operations Peculiar Modification,” SOPMOD for short.)

The US Army Infantry Center (USAIC) publishes a new edition of the Small Arms Master Plan (SAMP). The SAMP continues to outline objectives for a new family of infantry weapons. These are now named the Individual Combat Weapon (ICW), Personal Defense Weapon (PDW), and Crew Served Weapon (CSW). The ICW is to weigh no more than 10 pounds fully loaded, and be effective out to 500 meters versus troops wearing body armor. The ICW is also intended to be effective against vehicles and low flying aircraft. The PDW is projected to weigh no more than 1.5 pounds, and be capable of defeating troops wearing body armor at 50 meters.

AMCCOM awards a $923,000 delivery order to Colt related to the M16.

AMCCOM awards a $2,628,000 contract to FNMI related to the M16.

FNMI receives an order for 4,419 M16A2.

AMCCOM issues “Rifle M16 Stock & Guards: AMC National Training Center (NTC) Lessons Learned (LL) Program.” The author recommends changing the furniture material to Zytel.

Steyr’s Ulrich Zedrosser files multiple US patent applications for the design of the Steyr ACR.

The British ITDU restarts SA80 Hot/Dry Environmental Trials.

The Canadian government pays ARMS, Inc. for its set of standardized rail dimensions.

The BRL publishes “Live Fire Performance Evaluation of Optical Sights on the M16A2 Rifle.”

Candidates for the US Army’s Multi-Purpose Individual Munition (MPIM) competition submit Proof of Principle test rounds. Two of the three candidates are fired from launchers attached to the M16: the Brunswick RAW and the McDonnell Douglas Scorpion. The Scorpion Urban Fighting Weapon is another rocket-propelled weapon. Its launcher is attached underneath the barrel much like an overgrown M203.

The BRL submits “Candidate Fléchette Projectiles.”

The DOD begins a refurbishment program to update M16 and M16A1 rifles to the current M16A2 standard.

Colt Industries announces its intent to sell the Colt Firearms Division to CF Holding Company.

AMCCOM awards a $130,000 contract modification to Colt related to the 1967 Licensing Agreement.

The British ITDU ends SA80 Hot/Dry Environmental Trials.

HK delivers 15 additional ACR plus 90,000 rounds of ammunition in two batches (15,000 and 75,000).

The HK G11 receives type classification by the Bundeswehr.

A 6,000 round endurance test is run on the ACR candidates.

After Reed Knight witnesses press coverage of US soldiers during the invasion of Panama using duct tape, hose clamps, and other improvised methods to attach flashlights and other accessories to their weapons, KAC begins development of a modular accessory attachment system for the M16. Internally, the project is dubbed the “LEGO System.”

FN‘s Jean-Paul Denis and Marc Neuforge file an US patent application for the projectile design used in the 5.7x28mm SS90 cartridge.

(Next: 5.56mm 1990)

by Daniel E. Watters, Small Arms Historian
Post questions or comments at The 5.56mm Timeline’s Facebook page.

Document History
Publication: 12/10/1998
Last Revised: 05/17/2009


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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