The 5.56 X 45mm “Timeline” – 1960

A Chronology of Development by Daniel E. Watters


L. James Sullivan leaves ArmaLite.

On behalf of the US Army, Albert J. Lizza receives US Patent #2,920,538 titled “Bolt Mechanism for Firearms.”

CONARC issues “Approved Utility Characteristics for All-Purpose, Hand-Held Weapons.”

AAI’s first firing “burst simulator” is shipped to Aberdeen’s BRL. After initial adjustments, the device could simulate a cyclic rate of 2,300rpm.

Aberdeen’s BRL publishes “Provisional Estimate of the Wounding Potential of Fléchettes.”

The CWL publishes the report “Studies in Wound Ballistics – Temporary Cavities and Permanent Tracts Produced by High-Velocity Projectiles in Gelatin.” In these experiments, .30-06 M2 AP and M2 Ball, 45 grain .22 Hornet FMJ and JSP bullets, .30 caliber fragment simulators, and 1/4-inch steel spheres were fired into cylinders of 20 percent gelatin. Of note, energy absorption and momentum transfer in 20 percent gelatin are determined to be independent of temporary-cavity formation.

The US State Department’s Office of Munitions Control approves of the sale of 1,250 AR-15 to Indonesia.

The USAIB publishes the report “Evaluation of Single Fléchette.” The report covers testing of AAI’s “Arrow” fléchette cartridge using the modified Winchester rifles. For comparison purposes, both the short and long variants of the 6.35mm Simplex cartridges and 7.62mm NATO M59 Ball are also tested. Poor base accuracy, which deteriorated even further during use, is noted for the fléchette rifles, along with excessive muzzle flash and poor penetration against wood and sand. Comments are also made concerning the downrange hazard presented by the discarding sabot to friendly troops. The fléchette cartridges were found to be so lightly constructed that the case walls could be bent during handling. The cartridges had to be hand chambered individually, lest they be deformed during feeding from a magazine. On the positive side, the flat trajectory of the cartridge would require no sight setting changes out to 400 meters. Moreover, the future APHHW is projected to weigh roughly 3.5 pounds and possess a cyclic rate of 2,000rpm. Based on the projected characteristics, the fléchette is deemed to have a greater potential than the 6.35mm and 7.62mm NATO cartridges.

The OCRD reports back to the OCOApproval of MCs for APHHW.”

Gene Stoner files a patent application for a magazine design utilizing a constant force spring.

CONARC forwards the Infantry Board’s report on fléchette cartridge testing to Army CRD LTG Trudeau. CONARC concurs with the Infantry Board’s conclusions, and recommends that development of single fléchette ammunition be continued and directed toward, but not limited to, the correction of deficiencies listed in the report. Moreover, the improved ammunition should be submitted to the Infantry Board for further testing.

The US Army Arctic Test Board publishes the report “Evaluation of Single Fléchette and 6.35-MM Simplex and Duplex Ammunition.” In these follow-up tests, AAI’s “Arrow” fléchette cartridge, now designated the 5.6x53mm XM110, has been pitted against duplex and simplex versions of the short 6.35x48mm cartridge, 7.62mm NATO M59 and M80 Ball, and even the defunct .224 Springfield (.222 Rem Mag). (Additional details concerning the latter were excised.) The duplex 6.35mm cartridge is dismissed as having insufficient military value, and while the same complaints noted by the USAIB are repeated, the XM110 cartridge is deemed to be the superior choice for future development.

AAI’s second “burst simulator” is shipped to Springfield Armory.

On behalf of Winchester, Stefan Janson receives US Patent #2,935,915 titled “Gas-Operated Automatic Rifle Having a Plurality of Barrels.”

Colt requests new Ordnance testing of their improved AR-15 rifle. Dr. Carten refuses the request, citing the lack of military requirement for such a rifle.

Colt President Roff sends Cooper-Macdonald copies of the wire message from Dr. Carten denying Colt’s request for testing, a letter from Charles Dorchester outlining potential arguments for getting Carten’s decision overturned, a Congressional report with helpful statements made by Army CRD LTG Trudeau, and an Aberdeen test report.

Gene Stoner files a patent application for the triangle pattern forearm assembly.

The ORO publishes “Battle Sight Setting.”

The Infantry Board publishes “Evaluation of 6.35MM Simplex and Duplex Ammunition.”

AAI publishes the report “Final Summary Report – Small Caliber Demonstration Guns.”

In hopes of generating interest (and royalties) in the AR-15, Macdonald invites General Curtis E. LeMay, then Vice Chief of Staff of the US Air Force, to a combination 4th of July celebration/birthday party for former Fairchild president Richard Boutelle. Boutelle and LeMay are long-time friends and fellow firearms-enthusiasts. In fact, LeMay had previously attempted to have ArmaLite’s AR-5 survival rifle adopted for the USAF. At the party, LeMay is conveniently given an opportunity to shoot a new Colt-production AR-15 at a trio of watermelons. After bursting the first two melons at 50 yards and 150 yards, LeMay is suitably impressed with the terminal results. (Note: The third melon is spared the firing squad and is subsequently eaten.)

LeMay offers to recommend the AR-15 as a replacement for the USAF‘s aging stock of M2 Carbines, and it is arranged for three Colt AR-15 to be sent to the Air Force Marksmanship School at Lackland AFB for testing. LeMay also holds a meeting with the Army CRD LTG Trudeau, and representatives of Cooper-Macdonald. As a result, the OCO is asked to complete additional tests of the AR-15 rifle for the USAF.

Colt President Roff writes Cooper-Macdonald confirming Colt’s authorization for Cooper-Macdonald to represent Colt in attempts to get the AR-15 tested and approved by the US Government.

At the first of the month, the USAF Marksmanship School receives an additional five AR-15. Testing is conducted with Lackland Military Training Center’s commander General Robert M. Stillman, his Staff Officers, and Air Police personnel in attendance. Testing is conducted with both Remington and Norma ammunition. Accuracy testing is conducted using a mounted scope; however, there are problem with a loose scope mount. The AR-15’s ability to launch rifle grenades (both anti-personnel and anti-tank) is demonstrated. Gene Stoner and Charles Dorchester participate in the testing, and an AR-10 is demonstrated for comparison purposes.

A week later, Major Burton T. Miller of the USAF Marksmanship School sends the memo “Evaluation of AR-15.” Within, Miller notes that 10 AR-15 are now on-hand and that 5,000 rounds are scheduled for delivery. However, he anticipates that a total of 50,000 rounds will be needed, and wonders who is going place the order for additional ammunition and who will pay for it. Approval is requested to work out a test evaluation program with the Air Police School and the 3720th Basic Military Training School wherein a representative number of trainees will utilize the AR-15, firing the exact courses currently required for M2 carbine training. However, given the limited number of rifles, the AR-15 will need to be shuttled between the trainees and the range test staff conducting penetration, accuracy, and function testing.

During a staff meeting late in the month, General LeMay notes that a requirement exists for a better small arm for Air Force security forces to replace the M2 carbine. LeMay orders that an all-command survey be taken to validate the requirement and to determine the exact number of replacement rifles needed.

Fairchild Secretary Paul S. Cleveland writes Cooper-Macdonald laying out the relationship between the two companies.

  1. Cooper-Macdonald will attempt to secure an order and possibly a manufacturing license for ArmaLite weapons from India;
  2. Cooper-Macdonald will also attempt to secure approval from the US Government for sale of ArmaLite weapons to Military Assistance Fund (MAF) clients;
  3. In return, Cooper-Macdonald will receive 10 percent of any down payments and royalties from Indian licensing, and 10 percent of royalties from sales to the US Government and MAF clients; and
  4. The same terms as India’s will apply to any other foreign licensing deals made via Cooper-Macdonald’s efforts.

The USAF Marksmanship School publishes “Evaluation Report of the Colt-Armalite AR-15 Automatic, Caliber .223.”

General LeMay is briefed on the latest small arms development programs of the Department of the Army.

Dr. Carten is ordered to provide testing of the Colt AR-15 for the USAF. Ironically, the testing is requested to coincide with Ordnance testing of Dutch-production AR-10 rifles. Moreover, General LeMay, Army CRD LTG Trudeau, and other representatives from the USAF and Army will be in attendance for part of the testing. Mr. Sloan, a representative from the Federal Bureau of Investigation (FBI), also attends. Among the other observers are Gene Stoner, Robert Macdonald, and Gerald Gustafson, representing his current employer, the USAF Armament Laboratory.

Gene Stoner receives US Patent #2,951,424 titled “Gas Operated Bolt and Carrier System.”

Ordnance releases the Aberdeen D&PS test results on the AR-10 and AR-15 in separate reports. Once again, Laurence F. Moore’s recommendations and conclusions are missing. However, the remaining data is encouraging. For instance, the Colt AR-15 displays a malfunction rate of 2.5/1000 rounds (less than half of the 1958 Fort Benning tests).

In a report to the OCRD, Dr. Carten summarizes the AR-15 results as “reasonably satisfactory.” Thus, the Colt AR-15 is approved for USAF trials.

Colt Chairman Sidney A. Stewart writes Cooper-Macdonald to propose the following commissions to be paid on AR-15 rifles sold to the US Government:

Rifles Sold

Royalty Per Rifle
1-25,000 $1
25,001-50,000 $1.50
50,001-100,000 $1.75
Over 100,000 $2.00


The ORO publishes “Rifle Accuracies and Hit Probabilities in Combat.”

Ten AR-15 are sent to Lackland AFB for additional testing.

George Sullivan receives US Patent #2,965,994 titled “Gun Forearm.”

The US Army Chemical Research and Development Laboratory (CRDL) publishes “Wound Ballistics Assessment of Winchester-Western Caliber .25 Salvo Ammunition.”

(Next: 5.56mm 1961)

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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