The 5.56 X 45mm “Timeline” – 1970

A Chronology of Development by Daniel E. Watters



Dr. Carten, now Chief of the Technical Evaluation Branch of the AMC‘s Research, Development, & Equipment Directorate, submits the report “The M16 Rifle – A Case History to the Blue Ribbon Defense Panel.” Carten pins the primary blame for M16 malfunctions on the lack of specifications for case hardness. (Somewhere along the line, Colt reduced the strength of the extractor spring to help prevent rim shear. After it was found that this caused its own problems, Colt introduced the rubber nub insert for the extractor spring.)

WECOM issues “M16 Series Rifle Weapon System – Transition Plan.”

The US Army begins delivery of M16A1 to National Guard units.

Frankford Arsenal publishes the report “M16 Rifle/Ammunition Malfunction Modeling.”

Production of the XM177E2 ends.

CIS begins manufacture of M16S rifles in Singapore.

The US provides a military assistance grant of 83,762 M16A1 to South Vietnam.

The US provides a military assistance grant of 16,162 M16A1 to Laos.

The US provides a military assistance grant of 3,376 M16A1 to Cambodia.

ArmaLite experiments with coated projectiles in hopes of reducing bore friction. The coating is a new process developed by Du-Kote. ArmaLite also introduces the compact AR-18S.

C4 booby-trapped 5.56mm cartridges are encountered in the Phu Yen province of Vietnam. One soldier is killed and another wounded in separate incidents. EOD personal confirmed the contents. (Note: Dean has sources which indicate that conventional rifle primers should not be sufficient to detonate C4. However, I am including this claim from David R. Hughes for future reference. If Hughes’ claims are indeed genuine, perhaps the C4 acts as a bore obstruction for subsequent shots, inadvertently providing the desired destruction of the weapon.)

Frankford Arsenal produces a variant of the FA-XM sound suppressor for use on the XM177. These are intended for use by USAF Combat Control Teams (CCT).

Recently transferred from the USASASA to the T.J. Rodman Laboratory (Rock Island), AAI’s XM19 program continues to debug the design. Early in the year, the CDEC starts a new series of field experiments at Fort Ord using the XM19.

The British Director General Weapons (Army) instructs Royal Small Arms Factory (RSAF) Enfield to begin a two-year Preliminary Study to consider future replacements for the 7.62mm NATO cartridge and the L1A1 SLR. Calibers ranging from 4mm to 7.62mm are to be considered.

The West German Department of Defense completes a list of design criteria for a new combat rifle. These design criteria are as follows:

  • Total length of the weapon less than 750 mm
  • Total weight of weapon including 100 rounds under 4.5 kg
  • A minimum of 50 rounds on the weapon
  • Full performance even under adverse conditions
  • High hit probability in three round burst
  • An effective range without sight adjustment out to 300m

Spain restarts testing of the 4.6x36mm.

IWK experiments with a 4x37mm cartridge.

RWS introduces the 5.6x50mm Magnum. It is a rimless version of the 5.6x50mmR Magnum introduced two years earlier.

Secretary of Defense Laird approves the FY 1970 Taiwan MAP.

Olin admits that WC846’s manufacturing tolerances have played a role in cartridge performance. WC846 best suited for use in the 5.56x45mm is at the opposite tolerance end from WC846 best suited for 7.62mm NATO cartridges. Other manufacturers were not made aware of the differences. Henceforth, WC846 suitable for 5.56x45mm is relabeled as WC844. The remainder of the WC846 tolerance range retains the WC846 label.

Fort Benning performs weather resistance testing on brass and steel cased cartridges. The cartridges are test fired after 30 days of exposure.

ArmaLite submits to WECOM the proposal “Production of the AR-18 Rifle in the ROK Compared to M16.”

The Philippine Embassy in Washington DC expresses interest in a FMS purchase of 5,000 M16, 50,000 magazines, and 4.75 million rounds of 5.56mm ammunition. JUSMAG-PHIL and the US Embassy recommend against allowing the purchase. Instead delivery should be expedited of the 1,208 M16 programmed under the FY 1970 MAP. The rifles could be paid for by transferring the purchase of diesel fuel from the MAP budget to FMS funds. Admiral McCain suggests the alternative of allowing the 1,208 M16 to be purchased by FMS funds to allow MAP funds to be spent on other priorities. JUSMAG-PHIL indicates that the Chief of Staff of the Philippine military has stated that they would be willing to cover the cost of commercial consumables if delivery of the M16 can be expedited. With this, Admiral McCain forwards his recommendation to the JCS and Secretary of Defense Laird to expedite delivery of the 1,208 rifles along with ammunition.

Thailand receives 23,806 M16.

Frankford Arsenal releases the report “Elimination of Gas Tube Fouling in the M16A1 Rifle when using the M200 Blank Cartridge.” The culprit turned out to be the use of a white lacquer used by Twin Cities Army Ammunition Plant to seal the crimp of the blank cartridge. The titanium dioxide pigment in the white lacquer caused the observed fouling. Frankford recommends that clear or organically dyed lacquers be substituted for future M200 production runs.

Frankford also releases the report “Metallurgical Examination of Fouled Gas Tube and Flash Suppressor from an M16A1 Rifle.”

Aberdeen’s BRL publishes the report “The Gas Flow in Gas-Operated Weapons.” The theory presented here predicts the pressure history in the gas cylinder and the motion of the piston for a given pressure and temperature history in the barrel.

General Electric’s Armament Department publishes “Proposal for Development of a Special Purpose Individual Weapon.” This document covers their SFR/SBR developments to date. However, it appears that GE never receives any further funding to follow up on their recommendations, effecting shelving the revised GE/Springfield SPIW.

Secretary of Defense Laird announces that all US troops assigned to NATO duties will be equipped with the M16/M16A1.

All US Army infantry training has been converted from the M14 to the M16A1 rifle.

The US Ambassador indicates that the Philippine government still wants to purchase an additional 2,500 M16. The Embassy requests that if a FMS or commercial sale is approved, delivery of these rifles be withheld until after the MAP provided rifles are delivered. Admiral McCain concurs with the recommendation

Secretary of Defense Laird approves delivery of the 1,208 M16 to the Philippines from the FY 1970 MAP. He requests that Department of the Army deliver the rifles by April 25.

The US State Department approves the sale of 2,500 additional M16 to the Philippines.

The CDCIA publishes “Army Small Arms Requirements Study I (ASARS I): In-Process Review.” The purpose of ASARS is to develop documented data pertaining to the interaction of variable small arms characteristics, and the capability, through scientific method, of conducting subsequent trade-offs among these characteristics. The results of ASARS, in conjunction with the results of other ARSAP tasks, will assist in the development of the optimum small arms system for the future.

In hopes of preventing rim shear, Lake City experiments with 5.56mm cartridges using a thicker rim (0.055″ versus the standard 0.045″)

The USAIB at Fort Benning and Gerald A. Gustafson at Aberdeen each file a report titled “Product Improvement Test of Cartridges, 5.56-MM, Assembled with Steel Cartridge Cases.” The purpose of the test was to determine suitability of the 5.56-mm steel-cased cartridges to replace standard brass-cased cartridges, and to determine the physical and technical characteristics of the 5.56-mm steel-cased cartridges. Specific test phases to which the steel-cased cartridges were subjected were physical characteristics, safety, cartridge-weapon compatibility, adverse conditions (60-day open storage period), reliability, and human factors. There were no deficiencies and one shortcoming found: the susceptibility of the test cartridges to rust. There were 47 incidents of split cases out of 21,642 steel-cased rounds fired. However, these split cases did not adversely affect the operation of the weapons. There were 71 malfunctions with weapons firing control cartridges and 53 malfunctions with weapons firing test cartridges. All malfunctions, with the exception of three, were either weapon- or magazine-caused. The blast, flash, noise, and felt recoil produced by the test cartridges were comparable to those of the control cartridges. The test cartridges ejected farther to the rear and right than did the control cartridges. It is concluded that the steel-cased 5.56-mm cartridges are compatible with the M16A1 rifle and are suitable for US Army use under intermediate climatic conditions.

Remington’s John J. Scanlon files a patent application for a composite plastic body/metal head cartridge case.

On behalf of the US Army, Harold H. Wiese files a patent application for a disposable plastic magazine for the M16.

Because problems have been identified in the design of the weapons during engineering design tests by WECOM, the Stoner 63A1 are returned to Cadillac Gage for evaluation. The evaluation of these weapons leads to a redesign program.

Navy Ammunition Depot-Crane requests samples of the Colt CMG-2 for testing.

Secretary of Defense Laird returns the logistic management of M16 rifles to the services. Due the high demand and low supply of the M16 over the past four years, allocation and distribution of the rifles had been controlled by the Secretary of Defense, based on recommendations from the JCS.

Re-titled “Product Manager, Rifles,” COL Wing’s responsibilities are limited to the M16A1, XM203, and related ammunition.

The US Navy type-classifies the “Rifle, 5.56mm Mark 4 Mod 0.” This is a M16A1 modified for dedicated use with the HEL-M4A suppressor (AKA: Mk 2 Mod 0 blast suppressor) and optimized for maritime operations by the SEALs. Most of the operating parts of the rifle are coated in Kal-Guard, a quarter-inch hole is drilled through the stock and buffer tube for drainage, and an O-ring is added to the end of the buffer assembly. The weapon can reportedly be carried to the depth of 200 feet without damage.

Colt presents a contract proposal to the Philippine Embassy in Washington DC. The proposal indicates that 2,500 M16 will be shipped within 10 days after a letter of credit or cash payment is delivered to Colt.

Meanwhile, the Philippine military takes delivery of the 1,208 M16 from the FY 1970 MAP. The Chief of JUSMAG-PHIL note that this delivery brings the Philippine M16 inventory to 1,408. An additional 1,292 rifles are scheduled for future delivery under the FY 1971 MAP. Should the purchase of the 2,500 rifles be completed, the Philippines could have 5,000 M16 by mid-FY 1972. With this in mind, a technical data package for the manufacture of 5.56mm ammunition has been requested from the AMC to support a Philippine ammunition plant currently under construction. Completion is scheduled for mid-1971.

The Commander of MACTHAI informs Admiral McCain that the Thai government desires to establish a manufacturing capability for the M16. The Thai are requesting information on the availability of equipment and the cost for establishing the capability of producing 1,000-3,000 rifles per month. The Thai believe that the factory could serve a dual purpose of manufacturing civilian goods. While he believes the funds could be better spent on counter-insurgency efforts, the MACTHAI commander feels that the information should be provided so that the Thai government could make an informed decision. Admiral McCain concurs, and passes the request on to Secretary of Defense Laird. McCain requests that Laird comment on whether it is advisable to redirect the Thai government to the US Agency for International Development (AID) or commercial sources for developing a manufacturing capability.

Frankford Arsenal releases the report “Experimental Study of the Flow Characteristics in the Gas Tube of the M16A1 Rifle

Pier Carlo Beretta files an US patent application for the design of the AR70.

Colt’s Henry Into receives US Patent #3,507,067 titled “Grenade Launcher Having a Rotatable Forwardly Sliding Barrel and Removable Firing Mechanism.”

Shipments of M16A1 rifles to US Army NATO troops begin.

Frankford Arsenal releases the report “Evaluation of the 5.56mm Nosler Steel Bullet.”

The military specification for M193 Ball, MIL-C-9963D, is revised to MIL-C-9963E.

The military specification for M197 Tracer, MIL-C-60111A, is revised to MIL-C-60111B.

The GAO releases the report “Development and Cost of the Army’s Special Purpose Individual Weapon System.” It recommends that the US Army does not procure any further SPIW-type weapons until the cost of the ammunition can be reduced.

Rep. Ottinger charges that the SPIW has been developed by the US Army without the knowledge of Congress. He describes it as a “secret poison dart gun-type weapon” and “diabolical and inhumane”, shooting “flesh-ripping” darts.

The JCS informs Admiral McCain that current law and regulations do not provide for service funding of ammunition for the Philippine military. Moreover, there are no present stocks of the required ammunition to support the Philippines.

The CDCIA publishes the multi-volume “Army Small Arms Requirements Study I.”

Aberdeen publishes the report “Initial Production Test of Magazine, 30-Round, for M16A1 Rifles.”

Testing of the Colt CMG-2 begins at NAD-Crane.

The USAF‘s Marksmanship School releases the report “Evaluation of AR-18 Rifle.”

Hughes’ Morris Goldin files a patent application for the “lockless” firearm principle.

The South Korean MND announce that construction of a M16 manufacturing plant will begin within the year, contingent upon an US defense loan. Details are still being discussed with Colt.

US Army Foreign Science and Technology Center publishes “A Wound Ballistics Comparison of: Bullet, 43-Grain, 5.56-mm Ball, Soviet, MEN-29108 and Bullet, 55-Grain, 5.56-mm Ball, M193, US.”

Remington provides prototype grenade cartridges for launching the RAG-B ring airfoil grenade. These cartridges are later standardized as the M755.

The US Army approves an Advanced Development Objective for a new LMG, introducing the nomenclature “Squad Automatic Weapon.”

The British Jungle Warfare School’s Trial and Development Wing issues the report “Trial of Section 5.56mm Light Machine Guns.”

CDCEC publishes “XM19: Serially Fired Fléchette Weapon Evaluation.”

AAI publishes “Results of Engineering Study on SPIW Muzzle Device.”

Frankford Arsenal publishes the report “Ballistic Evaluation of 5.56MM XM287 Ball (68 Grain) and Matching XM288 Tracer Cartridge for XM207 Machine Gun.”

Testing of the Colt CMG-2 ends at NAD-Crane. After modifications are made, the three weapons are transferred to the SEALs for field testing.

France decides upon the 5.56x45mm for use in its new assault rifle.

The US Army awards a new $20.8 million contract to Colt (DAAF03-71-C-003). By January 1975, this contract’s orders will total 751,245 M16A1 and 2,300 M16 rifles.

In debate over the defense appropriations bill, Rep. Bray speaks out against eliminating funding for one of the three M16 manufacturers. Bray also mentions rumors that the production tooling from the eliminated source would be shipped to a foreign country for co-production of the rifle. Rep. Robert L.F. Sikes (D-FL) supports the elimination of one of the manufacturers for the saving of $14.3 million, but denies any knowledge of plans to move the tooling to another country. Rep. Bray points out that the original defense appropriations bill passed out of the House Armed Services Committee insisted on maintaining three sources of production, but that someone on the Appropriations Committee amended it to allow for funding only two sources. This was reportedly done on request from the Department of the Army. Rep. Philip J. Philbin (D-MA), chairman of the House Armed Services Committee, offers an amendment that would prevent the Army from procuring additional M16 unless three sources were maintained. The amendment is struck down 24 to 40.

An US business magazine reports that the US will allow South Korean M16 co-production despite the objections of congressmen and labor unions that this move will result in unemployment of US workers.

South Korean negotiations with Colt bog down again. The disagreement centers on patent royalties and treatment of US technicians.

Aberdeen releases the report “Military Potential Test of Short Range Cartridges, 5.56-mm Ball, 7.62-mm Ball, and 7.62-mm Tracer.” The objectives of the test were to determine the safety of the cartridges when fired from the M14 and M16A1 rifles and the M60 machine gun, and to compare cartridge characteristics and performance with that stated in the descriptive brochure. The cartridges with their short-range capability were designed for the training of military troops. The test cartridges differed statistically from values given in the manufacturer’s brochure in cartridge weight, projectile weight, propellant weight, cartridge length, and projectile length.

The British Armament Design Establishment (ADE) at RSAF Enfield creates a 5x44mm cartridge (roughly a .20/223 Remington), and an initial order is placed with Radway Green for test cartridges. Since 1969, the ADE‘s experiments have centered around the ’50s-era prototype EM2 rifle with its 7x43mm cartridge case necked down to 6.25mm. The change is inspired by a West German study indicating that future ideal military calibers will be 5mm or smaller. The final adopted 5mm projectile requires a 1-in-5″ twist. Existing AR-15, AR-18, and Stoner 63 rifles are converted to the new cartridge, including the belt fed Stoner 63 variant. Later, bullpup conversions of the AR-18 and Stoner 63 rifles are executed.

Olin’s Winchester-Western Division publishes “Summary and Recommendations – Multiple Fléchette Weapon System Development Contract.” Winchester reports that they have finalized a 9.53mm multiple fléchette cartridge with an aluminum cartridge case. The loadings include a standard four fléchette payload (4,240 fps), a pair of “ball” fléchette paired with a tracer, and even a specialized armor-piercing “penetrator”. Despite pushing pressures of up to 75,000psi, the large bore volume limits this to a brief spike, allowing the aluminum cartridge case to remain intact.

The South Korean MND announce that the US has agreed to formally transfer ownership of equipment and weapons (including the M16) currently issued to ROK forces deployed in Vietnam. The equipment and weapons will be shipped to Korea when ROK forces are withdrawn from Vietnam.

The last production lot of the white lacquer sealed M200 is completed at Twin Cities.

Frankford Arsenal releases the report “Contribution of the 5.56MM, Ball M193 Cartridge Metal Components to Gas Tube Fouling in M16A1 Rifle.”

The Institute for Defense Analyses publishes the report “Primer Selection for Small Arms Ammunition.” The paper examines the arguments for and against the Army’s prospective standardization of primers for 5.56mm ammunition. The question is essentially whether one manufacturer shall continue to use primers containing basic lead styphnate in primers for the 5.56mm cartridges that it produces at its own plant and at a Government-owned plant it operates or whether that manufacturer shall use primers containing normal lead styphnate, as do all the other six producers of these cartridges. Findings indicate that the continued use of basic lead styphnate would yield minor advantages in lower cost to the manufacturer, possibility in manufacturing safety, and in competitive environment, while standardization on normal lead styphnate would yield a minor advantage in primer performance and two significant advantages: a reduction in possible problems associated with future changes in cartridges and weapons and a reduction in the testing required.

Remington publicly announces the .17 Remington cartridge at their annual Gun Writers Seminar. (Oddly enough, H&R had already offered a production-custom line of bolt-action rifles chambered for a wildcat .17/223. However, the two cartridges are not interchangeable.)

On behalf of the US Army, Harvey H. Friend receives US Patent #3,538,635 titled “Combined Extractor and Ejector Mechanism for Automatic Grenade Launcher .”

The ODCSLOG‘s central point of contact for the M16A1 is discontinued.

WECOM‘s Systems Analysis Directorate publishes the report “Analysis of M16 Rifle Dispersion and Dimensional Data.” An analysis of the M16 rifle barrel dimensions and dispersion was conducted. Dispersion prediction equations were obtained using several categories of dimensional data. A discriminating procedure was developed suitable for use by field troops to separate barrels with “acceptable” dispersion from those “not acceptable”. Depth-of-muzzle-penetration by the erosion gage was selected as the discriminating variable.

The Chief of Staff of the Philippine military requests US approval of the FMS purchase of 4,000 M16. The US Ambassador and JUSMAG-PHIL support the request.

Frankford Arsenal publishes the report “Feasibility Study of Spin-Stabilized Subsonic Projectiles.”

Colt has completed delivery of all four IMP to the USAF.

(Next: 5.56mm 1971)

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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