The 5.56 X 45mm “Timeline” – 1973

A Chronology of Development by Daniel E. Watters



Congress deletes all but $3.6 million for the purchase of 37,533 M16A1 rifles in a supplemental defense appropriations request.

Twin Cities receives the first complete SCAMP production line. (SCAMP: Small Caliber Ammunition Modernization Program) The new production line includes high speed loading presses, with the goal of increasing cartridge production from 60-100rpm to 1,200rpm.

Frankford Arsenal contracts additional aluminum case testing to be performed by Thiokal Chemical Corporation. Frankford also develops an aluminum-cased blank cartridge, which Aberdeen finds to be equivalent in performance to the issue M200.

Gulf + Western Industries Inc. begins development of a plastic cased ball cartridge.

The US provides a military assistance grant of 82,446 M16A1, 157 XM177-type, and 13 M203 to South Vietnam.

The US provides a military assistance grant of 3,449 M16A1 to Cambodia.

The US provides a military assistance grant of 43,185 M16A1 to Laos.

The US provides 1,618 M16A1 to Indonesia as part of a military assistance package.

The US provides 700 M16A1 to Jordan as part of a military assistance package.

22,887 M16 rifles are deleted from the Philippine MAP.

CIS begins delivery of roughly 30,000 M16S rifles to Thailand.

The Danish Army begins testing of selective fire rifles to replace their M1 rifles. The M16A1 wins the testing, but the Danes are reluctant to adopt the 5.56mm cartridge outside of a wider NATO adoption. Instead, the Danes decide to lease 70,000 G3 rifles from West Germany. (The G3 had finished in 10th place in Danish testing.)

The US Army awards a rifle development contract to ARES, Inc. In return, Stoner creates the Future Assault Rifle Concept (FARC) prototype. Oddly enough, it is Stoner’s first 5.56x45mm design that hasn’t started life as an earlier 7.62mm NATO design.

After failed experiments involving conventionally arranged bolts, HK‘s G11 development team happen upon a solution for providing gas obturation with caseless cartridges. Their chamber and breech will rotate about an axis at a right angle to the barrel.

HK introduces a 5.56mm belt-fed LMG, the HK 23A1.

HK begins delivery of equipment to Thailand for their new HK 33 production facility, the Royal Thai Armory.

MAS completes ten A3 rifle prototypes.

Frankford Arsenal experiments with a 4.32x40mm cartridge. It is dubbed by some as the 4.32mm Optimum or 4.32mm Optimized.

Cartoucherie du Mans experiments with a 5.56x54mm cartridge.

FN experiments with a 3.5x51mm cartridge.

R&D work begins on the Civil Disturbance Control System. It is based on non-lethal variants of Abe Flatau’s Ring Airfoil Grenade (RAG).

ARMCOM officially begins operations.

Frankford Arsenal publishes “Study of the Pressure Distribution Behind the M193 Projectile when Fired in the M16 Rifle Barrel.”

The US Army CDC approves a Materiel Needs Document for a Future Rifle System (FRS). In many ways, it is a restatement of the SPIW requirements, incorporating both point and area target capabilities. However, the FRS is opened up to more than the previous fléchette cartridge systems. Among the requirements: The ability to maintain a rate of fire of 540 rounds every six hours for an entire day (15 grenade firings during the same six hour period). The point fire cartridge must be 25 percent more likely to incapacitate than the M193 from the M16A1. It must have a 30-50 percent probability of hitting a kneeling target at ranges from 300-500 meters. The area fire cartridge must be smaller than 40mm, yet maintain the lethality and range of the larger cartridge. The loaded weight of both systems combined must be less than 9-11 pounds. The point fire weapon is to display a minimum MRBS of 1,000 for the first 10,000 rounds fired. The area fire weapon is to display a minimum MRBS of 500 for the first 5,000 rounds fired.

Hughes’ Morris Goldin receives US Patent #3,713,240 titled “Lockless Firearm System.”

The Indonesian Minister for Defense and Security makes a personal plea to Vice President Spiro Agnew requesting additional military assistance. Among the requests is the desire to establish a domestic manufacturing plant for either the M16 or AR-18.

NATO‘s Action Committee 225 (AC/225) Panel III, Subpanel 4 issues “Operational Requirement for Light Support Weapon.”

The British ADE is at work developing a rifle design for their 4.85x49mm cartridge. The Project Leader is Col. John Weeks, and the rifle design team is led by Sydney Hance. (Hance had been chief design assistant for the EM2 rifle.) The resulting IW and LSW are both equipped with separate, push-through selector and safety buttons. While the IW fires from the closed-bolt position in all modes, the LSW fires from a closed-bolt position only in semi-auto mode. 3 round burst and full-auto fire are from an open bolt position. In addition, at least one prototype is chambered in 5.56x45mm for comparison purposes.

Prototype 4.85x49mm ammo is created by reforming fired 5.56mm blank cartridges from FN.

The US Army Arctic Test Center testing of the M203 is terminated pending design reevaluation and a product modification to correct primer punch-out problems. The latter problem had also been identified as an issue during 1969 testing at Aberdeen.

The FY 1973 Indonesian MAP is cut nearly in half. The US Ambassador to Indonesia suggests possible concessions to soften the blow. These mirror the previous month’s requests by the Indonesian Minister of Defense and Security. CINCPAC Admiral Gayler concurs in the need to make some concessions, but recommends that the small arms plant be reserved for a joint study proposal. The US State Department points out that the establishment of an Indonesian small arms plant is already being negotiated on a commercial basis.

The military specification for the M16 and M16A1 rifles, MIL-R-45587, is revised to MIL-R-45587A.

The US Army Arctic Test Center publishes the report “Product Improvement Test of Gilding Metal Clad Steel (GMCS) Jackets for 5.56MM Projectiles.” The testing had been conducted on behalf of Frankford Arsenal.

The US Army Arctic Test Center issues the report “Check Test of Launcher, Grenade, 40mm, M203, under Arctic Winter Conditions.”

TRW ceases development of the LMR.

Morris Goldin files a patent application for the design of the plastic-cased “chiclet” cartridge.

Frankford Arsenal publishes “Determination of Normal Forces Arising from In-Bore Pressures on an N-Segmented Sabot: Single Fléchette.”

Radway Green delivers the first purpose made 4.85x49mm cartridges.

Colt’s Stanley Silsby receives US Patent #3,724,325 titled “Rate Reducer.”

On behalf of the US Army, Warren W. Wells receives US Patent #3,732,643 titled “Cartridge Magazine.”

Aberdeen’s BRL releases the memorandum report “Analysis of Exhaust Gases from the XM19 Rifle — An Application of Gas Chromatography/Mass Spectroscopy.” A technique combining gas chromatographic and mass spectrometric analysis was developed and applied to determine the chemical composition of gases resulting from firing the XM19 rifle with the XM645 fléchette round. Cyanogen, carbonyl sulfide, carbon monoxide, nitrous and nitric oxides were among the products detected.

The Israeli Defense Forces (IDF) issue its first batch of IMI Galil rifles.

HK‘s Tilo Möller and Dieter Ketterer receive US Patent #3,731,417 titled “Firearms.”

The Philippine government announces that it will accept Colt’s proposal for establishing a domestic small arms plant. The agreement will call for the direct purchase, initial in-country assembly and eventual production over a six year period of 150,000 rifles and the equivalent of 22,500 rifles in spares.

Proposed Philippine Rifle Program

Month Quantity Activity Local Content
0-9 5,000 Assembled by Colt 0 Percent
10-18 15,000 Local Assembly 10 Percent
19-21 7,500 Local Assembly/Production 20 Percent
22-24 7,500 Local Assembly/Production 50 Percent
25-36 30,000 Local Assembly/Production 80 Percent
37-48 40,000 Local Production 100 Percent
49-60 45,000 Local Production 100 Percent
61-72 22,500 Local Production of Spares 100 Percent


The Chief of JUSMAG-PHIL informs CINCPAC Admiral Gayler that the Philippine government has requested approval of a FMS loan to finance the local co-production program.

Frankford Arsenal publishes the report “A Limited Analysis of a New Ammunition Concept for Potential Future Rifle Application.” This report concerns the FABRL “low-impulse” cartridge, created in a joint project between Frankford Arsenal and Aberdeen’s Ballistic Research Laboratories (BRL). (While it is clear that the initials FABRL indicate the parent agencies, it is later explained away as: “Future Ammunition for Burst Rifle Launch.”)

The original projectile shape chosen by the BRL is the “AR2 artillery shape”; however, this proves difficult to manufacture. A slightly shorter compromise projectile known as the “Von Korman” bullet is used instead. This projectile weighs 32 grains as manufactured. The idea is that if the long, low drag projectile is launched at the same velocity as the shorter 55gr M193 projectile, the two cartridges will exhibit in similar trajectories. The lighter projectile will also provide the side benefit of reducing recoil by a third in comparison to the M193. Testing indicates that the “low-impulse” FABRL cartridge could improve the average probability of incapacitation by 60 percent over the M193, between the ranges of 0 to 500 meters.

Since the lighter “Von Korman” projectile does not need as much propellant to reach the target velocity, it is realized that the FABRL cartridge case could be made shorter. Experiments with the shorter case leads to additional experiments with aluminum cases, achieving an overall cartridge weight of 87 grains versus the ~182 grain weight of the M193 cartridge.

MAS publicly introduces its new 5.56mm bullpup Fusil Automatique. This is better known as the FA MAS, or FAMAS.

HK‘s Tilo Möller and Dieter Ketterer receive US Patent #3,736,686 titled “Automatic Hand Firearm with Interchangeable Magazine.”

The USASASA is disestablished.

Control of the SAW project is passed on to Rodman Laboratory.

Remington’s John J. Scanlon receives US Patent #3,745,924 titled “Plastic Cartridge Case.”

Fairchild Industries’ John F. Dealy and Michael W. York receive US Patent #3,742,636 titled “Firearm Having a Carrying Handle and Associated Rear Sight.”

Aberdeen’s BRL issues the report “A hybrid computer model of the XM19 weapon.”

The Philippine Secretary of National Defense requests an FMS loan to partially finance the M16 co-production project. The loan would be for $15,614,000, divided into two annual installments: $8,622,000 in FY 1974 and $6,992,000 in FY 1975. The Philippine government requests that repayment be conducted over a period of 10 years, in eight equal annual installments following a two year grace period. The Philippine government will obtain additional foreign and domestic financing to fund the remainder of the project.

CINCPAC Admiral Gayler supports MACTHAI‘s recommendation for an one-time exception to MAP policy to provide 4,600 M16 to the Thai Border Police and National Police.

Frankford Arsenal publishes the report “An Analysis of Various Primer Vent Configurations in 5.56mm Ammunition.” Statistical techniques were used to determine the ballistic effect of various primer vent configurations in 5.56mm ammunition. The results indicate that the 5.56mm standardized primer vent provides the most efficient ballistic system (i.e., the highest velocity-pressure ratio) of all vent configurations tested. Velocity, chamber pressure, action time, propellant ignition time, temperature coefficient of velocity, and the temperature coefficient of chamber pressure are all affected by a change in primer vent cross-sectional area.

Aberdeen publishes the report “Development Test III of Cartridge, 5.56-MM, Aluminum, Blank.”

The US Embassy advises that it strongly recommends US support for the Philippine M16 co-production plan and approve the Philippine request for FMS credits, preferably out of FY 1974 and 1975 funds. The rest of the US Country Team and CINCPAC Admiral Gayler also recommend approval. The Embassy points out that the Philippine government will go ahead and establish a small arms factory, with or without US support. HK appears to be their backup choice.

Frankford Arsenal publishes the report “Stress Corrosion Susceptibility of Aluminum Cartridge Cases.” The report concerns the investigation of stress corrosion cracking of experimental aluminum cartridge cases in a 6 percent sodium chloride boiling solution. The 5.56mm cases were of 7475 aluminum alloy, tempered to T6 or T73 condition, and the empty cases were assembled with projectiles to represent the stressed condition of finished cartridges. Stresses applied to the mouth rim and neck of the cases were calculated from the interference (i.e., projectile diameter versus internal diameter of the case mouth and the case neck wall thickness.) For each of three calculated stress levels, a range of failure times was observed.

William B. Ruger and Harry H. Sefried, II file a patent application for the three-round burst mechanism of the AC556.

Colt’s George Curtis and Henry Tatro receive US Patent #3,756,119 titled “Machine Gun.”

Andrew J. Grandy files a patent application for folded path ammunition and weapon systems.

Rodman Laboratory publishes the report “Rifle-Gas Launched Grenade Concept.” The report describes a feasibility study on a novel approach for launching a 40mm grenade. The study was undertaken with the goal of conceiving and developing a future grenade launcher which would be applicable to the Future Rifle System Program. This program advocates a weapon system which is a combination of both a rifle (point fire) and a grenade launcher (area fire). To maximize integration of the launcher to the rifle design, it was theorized to utilize rifle propellant gases to launch a grenade projectile. The proposed concept would provide for reduced grenade ammunition costs, reduced number of launcher component parts, lighter total weapon system weight, and more grenade rounds per combat load. A concept which contained all of the above features was generated, designed, fabricated, and tested.

Colt announces the signing of a preliminary agreement with the Philippines to establish a M16 manufacturing plant. The license, held by the Philippine government, will last 10 years and allow for export of an additional 65,000 rifles. The license includes a M16A1-type rifle and a 14.5″ barreled carbine. Colt designates these variants the Model 613P and 653P, respectively.

On behalf of the US Army, Leonard R. Ambrosini and Charles N. Bernstein file a patent application for the design of an external tracer projectile.

Frankford Arsenal publishes the report “Analytic Study of Extraction Forces in the M16 Weapon.” A parametric study involving six geometric and materials parameters for both conventional brass and 7475 (TMT) aluminum 5.56mm cases in the M16 weapon is presented. Results defining the lowering of extraction force in terms of six materials and design factors are stated. It is found, based on these results, that the aluminum case is superior to brass in ease of extraction.

Philco-Ford publishes the report “Process Development and Characterization of Chemical Vapor Deposited Tungsten for Gun Barrel Applications.” A 20-month program was conducted to develop improved chemical vapor deposition (CVD ) processes for applying tungsten to the bores of gun barrels, and further, to characterize the physical and mechanical properties of the CVD tungsten as deposited. Conventional and high strain-rate tensile and compression tests were conducted on CVD tungsten as deposited on 4150 steel at temperatures of -65 F, ambient, and 200 F. Density, thermal expansion, and thermal conductance measurements were also made. Barrel materials of CG-27, L-605, 718, and Pyromet X-15 were also investigated. Based on test firings, acceptable CVD tungsten adherence was demonstrated on 4150, but the other four alloys revealed only marginal quality. Fourteen MG3 test barrels of the five materials (chambered in .220 Swift) were fabricated and delivered to the USAF.

Rodman Laboratory publishes the report “Effect on the M16A1 Rifle of Firing .22 Caliber Ammunition.” A 25,000 round test program was conducted to determine the effects on the M16A1 Rifle of firing up to 10,000 rounds of .22 caliber rimfire ammunition through it. No significant permanent degradation of the rifle was found.

Rodman Laboratory also publishes the report “Holographic Analysis of Small Arms Barrels.” Double-pulse holography techniques were used to observe gun-barrel deformation and motion during firing. Radial barrel deformations of an M16 barrel of approximately 0.0002 inch were observed.

Colt’s Henry Into receives US Patent #3,774,500 titled “Machine Pistol.”

HK‘s Tilo Möller and Dieter Ketterer receive US Patent #3,774,498 titled “Charging Device for Automatic Firearms.”

Andrew J. Grandy files another patent application for a “folded path” cartridge and weapon system.

Secretary of the Army Howard H. Callaway establishes the Army Materiel Acquisition Review Committee (AMARC) to conduct a comprehensive review, analysis, and critique of the Army’s materiel acquisition process. Recommendations for improvement are to be made, with concentration on procedures and organization (especially that of the AMC).

The DOD informs CINCPAC Admiral Gayler that it supports the Philippine M16 co-production plan; however, further action is awaiting State Department concurrence. The US Ambassador reemphasizes his support for the plan.

Rodman Laboratory publishes the report “M16A1 Rifle Accuracy Parameters.” An accuracy test program was conducted to determine which factors if any limit the accuracy of the M16A1 Rifle, those factors being looseness of the weapon’s components, lubrication, corrosion, mixing of different types of ammunition, and types of rests used.

Aberdeen publishes the report “Product Improvement Test of Cartridge, 5.56-MM, Ball, M193 with Gilding-Metal-Clad Steel-Jacketed Projectile.”

ARMCOM removes fléchette cartridges from “immediate consideration” for use in the Future Rifle System Program.

On behalf of the US Army, Robert F. Magardo, Leonard R. Ambrosini, and Raymond S. Isenson file a patent application for their version of the Dual Cycle Rifle.

HK‘s Tilo Möller and Dieter Ketterer receive US Patent #3,777,381 titled “Firearm Carrying Handle and Sight Protector.”

Andrew J. Grandy files yet another patent application for a “folded path” cartridge and weapon system.

Abe Flatau, Donald N. Olson, and Miles C. Miller file another patent application for the Soft RAG.

On behalf of the US Navy, Robert A. Leverance and Morrison B. Moore, III receive US Patent #3,776,093 titled “Muzzle Blast Suppressor.”

(Next: 5.56mm 1974)

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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