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John S. McCain POW CIA-Defense Department Documents

 Vietnam War: M-16 M-14 and Other Rifle Groups

Vietnam War
M-16 M-14 and Other Rifle Groups
Department of Defense Reports, Field Manuals, and Training Film


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2,780 pages of reports and manuals by, and created for the Department of Defense, dating from 1961 to 1980 and one 1966 US Army training film on the M16 Rifle and other rifle groups.

Concurrent mention is made in these reports of other rifles such as the Armalite AR-15, AR-18, M14E2, M-60 grenade launcher, M-79 grenade launcher, and M203 grenade launcher, Soviet/satellite AK-47, Stoner 63 guns (5.56-MM), S-C and C-SMG.

The standard rifle used by the U.S. Army as American involvement in the Vietnam War grew was the M-14. In 1960, Colt introduced the AR-15 semiautomatic rifle. This was later developed into the United States Rifle, Caliber 5.56 mm, M16, the U.S. military's version of the ArmaLite AR-15 rifle.  The M16 would eventually replace the M14 rifle in Vietnam as the standard weapon of the U.S. Army during the Vietnam War. General dissatisfaction with the M14 and numerous studies led the Army to the development of a light weight weapon capable of firing a burst of small caliber bullets with a controlled dispersion pattern. The M14 Rifle was designed primarily for semi-automatic fire. The magazine fed, gas operated M14 had an effective range of 500 yards, and used a standard NATO 7.62mm cartridge in a 20-round magazine.

In the early 1960's, U.S. Special Forces in Vietnam used the AR15 and it was given glowing reports. Although opposed by the Ordnance Corp, the Armalite AR-15 was adopted by the Secretary of Defense as the 5.56mm M16 rifle.  In November 1965, the 1st Cavalry Division turned back North Vietnamese regulars in a savage battle in the Ia Drang Valley. LTC Harold G. Moore lauded the new M16 rifle his troops had used. "Brave soldiers and the M16 brought this victory," he declared.

The M16 was selectable for full and semi-automatic fire.  The M16 was to have had the same effective range as the M14 rifle it replaced, but it was most effective at a range of 215 yards (200m) or less.  The M16 used a 5.56mm (.223 cal.) cartridge in 20- or 30-round magazines.  Some in the field found that the M-16, 55-grain, 5.56-millimeter bullet had a few disadvantages over caliber .30 projectiles past 300 yards. Out to 300 yards it was found to be able to shoot through a steel helmet or a flak jacket. Beyond 300 yards, however, many reported that the Ml6 was not too effective. A great advantage of the M16 and its ammunition was its lightness. The M14 and 100 rounds in magazines have a weight of 16.5 pounds. The M16 and 250 rounds also weighed 16.5 pounds. Meaning that each combat soldier and Marine could carry at least twice as many rounds for the same weight.

Many young Americans serving in the field during the Vietnam War found that the necessary cleaning procedures for the M16 were too time consuming. It was believed that burst-fire accuracy was not as good as it might have been if the rifle had been designed to fire more slowly and had a slightly different stock. Still most saw the M16 as much better at full automatic than the M14 modified to automatic, fired in the same manner. Another inherent disadvantage of the M16 was its tendency to waste ammunition. All burst-fire weapons do this to some extent.

There were a number of serious problems encountered during initial fielding. Initially, the rifle was the target of criticism because it would unexpectedly stop firing. The fussy M16s responded poorly to wet, dirty field conditions, and often jammed during combat, resulting in numerous casualties. Keeping the gun clean in the field in Vietnam was difficult. Modifications and a late 1966 redesign were made on the weapon, along with an effort to train the troops in its care and cleaning. The reliability of the M16 significantly improved. It proved particularly valuable in the close jungle firefights experienced during the Vietnam War. As a result of better training, preventive maintenance, and several design changes, the weapon that has become the standard issue rifle of the U.S. Army (3,690,000).

On 28 February 1967, the United States Army adopted the XM16E1 rifle as a standard United States M16A1 rifle, 5.56mm

The current versions of the rifle are models M16A2 and M16A4.

Material on the disc includes:


Rifle 5.56mm, XM16E1, Operation and Cycle of Functioning TF9-3663 (1966)

A 20 minute Vietnam War era US Army Training Film on the XM16E1 rifle. The first mass-fielded version of the M16 rifle. This is the version with chrome-plated bolt carrier, no trap door in the buttstock, without forward assist, non-chrome-lined chamber, and three-prong flash suppressor. Somewhat notorious for reliability issues in the jungles of Vietnam, it was upgraded into the much more reliable M16A1 in 1967.


FM 23-9

Department of the Army Field Manual, FM 23-9 July 1966(RIFLE, 5.56-MM, XM16E1)

This manual provides, guidance for presenting instruction with the Rifle, 5.56-mm, XM16E1. It contains a detailed description of the rifle and its general characteristics, procedures for disassembly and assembly, operation and functioning of the rifle, types of ammunition, and maintenance.

Topic covered include: General characteristics; Disassembly and assembly; Field stripping; Operation and functioning; Care and cleaning; Stoppages and immediate action; Ammunition; Destruction of materiel to prevent enemy use; Preparatory marksmanship; Automatic fire; Sight adjustment; and Battlesight zero.

FM 23-8

Department of the Army Field Manual, FM 23-8 May 1965 (U.S. Rifle 7.62mm, M14 and M14E2)

This manual is a guide for commanders and instructors in presenting instruction in the mechanical operation of the M14 and M14E2 rifles. It includes a detailed description of the rifle and its general characteristics; procedures for detailed disassembly and assembly; an explanation of functioning; a discussion of the types of stoppages and the immediate action applied to reduce them; a description of the ammunition; and instructions on the care, cleaning, and handling of each weapon and its ammunition.

FM 23-71

Department of the Army Field Manual, FM 23-71 July 1964 (Rifle Marksmanship)

This manual provides training guidance in developing and maintaining the rifle marksmanship proficiency of the individual soldier. This manual contains detailed information on conducting training in fundamentals of individual rifle marksmanship, battlesight zero, field firing, target detection, record firing, individual night firing and sniping.


Rifle Squad and Platoon Evaluation Program 22 May - 31 July 1961. Annexes A-I

The Commandant, USAIS, expressed concern over problems resulting from the introduction of certain new weapons into current organizations; specifically mentioned were: (1) the loss of the multi-shot capability of the M79 grenade launcher justified the need to examine whether the decision to place two of these weapons in each rifle squad remained a valid one. (2) The demonstrated inaccuracies of the M14 rifle (modified) and its inability to maintain a high rate of fire made it a doubtful substitute for the BAR in satisfying the automatic fire requirements of the Rifle Squad. (3) Substitution of the M60 machine gun for the M14 (modified) rifle in the Rifle Squad should not be accomplished without careful consideration of the tactical and logistical implications involved. The Commandant, USAIS, directed that tactical field testing be conducted at Fort Benning to determine an optimum Rifle Squad and Platoon which provides the best balance of personnel, weapons, equipment, and tactics for the present time frame.

Rifle Evaluation Study December 08, 1962  
Rifle Evaluation Study December 20, 1962 

Two studies by the Infantry Combat Developments Agency at Fort Benning, Georgia. The reports state that recent correspondence and memoranda initiated within, and between, the Department of Defense and Executive Agency of the United States Government has indicated that the M14 rifle is interior to the Armalite AR-15 rifle and the Soviet/satellite AK-47 rifle. Views of the Department of the Army were requested on the relative merits and effectiveness of the subject weapons.

The Department of the Army directed that an evaluation study be conducted on doctrine and concepts of employment of small arms weapons to determine requirements for and desired military characteristics of these weapons. Concurrent with this study effort, a world-wide comparative evaluation was conducted by the US Army, through field test, to determine the relative firepower effectiveness of the AR-15 and M14 rifles.

In conduct of the doctrine, employment and requirements portion of the rifle evaluation study, tactical aspects and utility of the candidate weapons were to be considered. Using merits and attributes of each weapon considered a set of hypotheses and courses of action to be pursued were established to determine the most suitable weapon and appropriate action to be undertaken. Factors and hypotheses to be considered were: (1) Range requirements for rifles and machineguns.  (2) Role of the machinegun. (3) Requirements for the machinegun in light of an automatic rifle firing capability. (4) Requirements for rifle grenade launchers. (5) Requirement for firing from armored personnel carriers (6) Requirement for the bayonet and for each rifle to accept the bayonet. (7) Impact on doctrine and employment when employing a five to seven man rifle squad. (8) Comparative attributes of the AR-15, M14 and AK-47 rifles and the preferable rifle if an equipment modernization program decision was to be made. (9) Advisability of introducing AR-15 or AK-47 type under currently existing conditions. (10) Appropriate course of action to be pursued from rifle development and procurement aspects.

The methodology used in approaching this study is an analysis and requirements of the basic combat unit of the US Army; the Infantry squad. Although the individual soldier is the major user of small arms weapons, he does not function in battle as an individual. Rather, he functions as a member of a team - the squad - and cannot be considered in isolation. Doctrine and concepts of employment envision teamwork between combat elements. Since the Infantry squad is the basic combat unit, it is considered the most valid organization for evaluation of doctrine, employment and requirements for small arms weapons.


A September 1964 report by the US Army Test & Evaluation Command.  The purpose of this test was to determine if production-line samples of M16 rifles would comply with performance specifications; to detect any design, manufacturing, or inspection deficiencies; and to determine the accuracy and the ability of the rifle to function when subjected to automatic-fire roles and under various adverse conditions. The test was conducted between 26 May and 14 September 1964.  The report concludes the rifles produced satisfactory performance except that one had an excessive number of failures to fire semiautomatic (single rounds) in the reliability test.


A 600 page December 1965 report by the United States Army Infantry Board (USAIB), Fort Benning, Georgia. The report found that there were no significant differences between the SAWS weapons except for reliability. It found that the current standard weapons were the most reliable. The M14, M14E2, and M60 were significantly more reliable than their counterpart SAWS weapons. The use of duplex ammunition significantly increases hit capability. The USAIB recommended that no consideration be given to adoption of new weapons systems until a significant improvement over the standard 7.62-mm systems could be achieved.

Reports of Engineering, Service, and Service-Type Tests of Small Arms Weapons Systems (SAWS)

A December 13, 1965 report by the U.S. Army Armory Board at Fort Knox, Kentucky. Reporting on service testing of the S-C and C-SMG as vehicular-stowed weapons on combat vehicles for local security purposes and other dismounted action was conducted. The report found that S-C and the C-SMG offered significant advantages over the current standard caliber .45 Sub-Machine Gun, M3A1 in range, general utility, safety, and handling characteristics for its intended purpose, that the S-C as tested was suitable for US Army use as a combat vehicle-stowed individual weapon and that the C-SMG would be suitable when the deficiency is corrected, and that both the S-C and C-SMG were safe for their intended use. It was recommended that, subject to action by Department of the Army to adopt 5.56mm weapons on a scale for general use by ground troops, the S-C weapon be adopted for US Army use as a vehicle-stowed individual weapon for combat vehicle crew members.

The adoption of the 5.56mm, MI6/MI6E1 Rifle for US Air Force use and limited Army use stimulated the interest of industry in developing other weapons in this caliber for military use. In 1963-64, the Advanced Research Projects Agency (ARPA), Department of Defense, directed and coordinated Army and Marine Corps tests of the S-C Weapons System, a family of six 5.56mm weapons which featured interchangeability of components. Army tests were limited to those necessary to determine the military potential of the system, while the Marine Corps conducted service and troop tests. The results of the Army tests indicated that the S-C weapons were accurate and of good basic design, but that the machineguns appeared to be marginal in operating power and deficient in barrel life.

The S-C is a lightweight, 5.56mm magazine-fed. Gas operated front-locking, rotary-bolt weapon cable of firing in either semi- or full-automatic mode at a cyclic rate of 660 rounds per minute. It is a closed-bolt type, and has a short barrel assembly and a folding buttstock.

The C-SMG is a 5.56mm gas-operated, air-cooled. Magazine-fed, semi- or full-automatic shoulder weapon which fires at a rate of 750 rounds per minute. It feeds from a 30-round magazine, fires from a closed bolt, and has a telescoping buttstock.

A Preservative-Lubricant for Small Arms

A 1968 report from the Naval Research Lab. It reports on a protective and lubricating coating that was developed for use on the M16 submachine gun and other small arms. It protects the M16 submachine gun used by SEAL and UDT personnel during immersion in sea water and exposure to sand, dust, and jungle environment. Treated weapons are ready for immediate use. The preservative-lubricant coating which was developed for this application is a compound of arachidyl-behenyl amine and tetrapropenylsuccinic anhydride, with oil and a solvent. It was packaged in aerosol cans for field use. The spray penetrates and displaces water from wet surfaces. The dried coating is firm and non-tacky but breaks down to a grease-like consistency between moving parts. The consistency of the coating material can be completely controlled by adjustment of the formulation. It is compatible with other lubricants. The coating provides excellent corrosion protection, because the entire solid phase consists of a waxy polar inhibitor. The oil phase, carrying the inhibitor in solution, can creep out to protect scratches and worn areas in the coating. Metal specimens and complete weapons were protected from damage during exposure to sea water for 3 days.

M14 Rifle Cost Analysis Report

An October 1968 Report by the Army Materiel Command, Systems and Cost Analysis Division. The report summarizes the system history and the development, investment, and operating costs of the 7.62mm M14 rifle. Development of the rifle occurred from 1945 to 1956 and totaled $10.9 million. Overall, 1.38 million rifles were delivered from 1960 to 1965 by four manufacturers at an average cost of $105.15 each. The production learning (experience) curve had a slope of 92 percent. The annual operating costs per year per rifle for maintenance (includes repair parts, direct and general support facilities, and labor) was about $50.52 per year.

Engineer Design Test of 20-Round Plastic Magazine for M16A1 Rifles

An October 1969 report from the Aberdeen Proving Ground, Materiel Testing Directorate. The document reports on a series of engineering design tests of 20-pound plastic magazines of 6-10 nylon with 50% fiberglass reinforcement, for the M16A1 rifle. Equal numbers of test and control magazines were subjected to a series of comparative evaluations to determine function performance characteristics and material durability at 65 F, +155 F, and ambient range temperature (+70 F plus or minus 30 F), and in adverse conditions of mud, sand, dust, and water. The test magazine material was checked for compatibility with various nonstandard solvents and lubricants. A displacement time study was made of the magazines to determine cartridge positioning characteristics during firing. The test results reveal that the test magazine required further design engineering to improve performance in adverse conditions and to increase material durability at low temperature.

Product Improvement Test of Cartridges, 5.56-mm, Assembled with Steel Cartridge Cases

A March 1970 report from the Army Infantry Board, Fort Benning, Georgia. 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 was concluded that the steel-cased 5.56-mm cartridges were compatible with the M16A1 rifle and were suitable for US Army use under intermediate climatic conditions.

Analysis of Dispersion Measurements for the M16A1 Rifle with Chrome Plated Bore

A January 1975 report by the Army Material Command. This report is a result of the higher than expected wear out rate of barrels used on the M16A1 rifle during its use in Vietnam during the Vietnam War. The wear out rate was due to the normal mechanical erosion plus the corrosive effect of the Vietnam environment. To correct this problem, it was decided to chrome plate the bore of all replacement barrels. The sample barrels selected from three manufacturers were fired until they were worn out with accuracy checks taken after each thousand rounds fired. The average value of the extreme spread measure of dispersion was used to establish acceptance and rejection criteria for new barrels and to establish the amount corresponding to a worn out barrel.

An Analysis of the Infantry's Need for an Assault Submachine Gun

A June 1977 research report from the Army Command and General Staff College, at Fort Leavenworth, Kansas. This study was undertaken to determine the proper role of the small arm in the mechanized rifle squad and investigate a requirement for an assault submachine gun light enough and small enough to improve the capability of the mechanized infantry squad to better perform its mission with increased firepower. The results of historical studies and current doctrinal development literature were used to determine the proper role of the individual small arm in combat related to supporting weapons. Two essential elements of analysis served as the basis of the argument. The first deals with the types of effective fire required by the infantry small arm, and the second, with expected engagement ranges requiring effective fire. Component factors of the elements of analysis are target effects, sustainability of effects, tactical employment of the rifle squad, effectiveness by range, small arms characteristics and the doctrinal role of the small arm. The conclusions were that the adoption of a compact, lightweight assault submachine gun would enhance the capability of the mechanized infantry squad to accomplish its mission by improving target effects, sustainability of effects, tactical versatility, mobility, and maneuver. Further, that the psychological impact on the esprit and élan of its users would collectively be advantageous.

Summary of the ARI-Benning Research Program on M16A1 Rifle Marksmanship

This 1980 report summarizes the major products of research on rifle marksmanship conducted by the Army Research Institute at Fort Benning, mostly between March 1978 and June 1980. It includes research designed to identify the problems existing in basic marksmanship training and training equipment (e.g., poor instruction, insufficient practice and inadequate knowledge of shooting results). Several experiments are reported that examined promising solutions to these problems. These solutions include simplified fundamentals, an improved zeroing target, better diagnostic check points, down-range feedback and other procedures to improve knowledge of results, improved transition to firing and steps to improve instructional quality. Based upon the research findings, a new basic rifle marksmanship program was developed and tested. It was found to improve record fire (final exam) performance by 29 percent. This new program was put into effect in the Infantry Training Brigade at Fort Benning and was soon adopted Army-wide. The report also summarizes the main problems remaining to be resolved if fully adequate basic marksmanship training was to be realized. It concludes with information about the continuing research directed toward development of improved advanced individual and unit level training in marksmanship.

FORSCOM/US Army Marksmanship Unit M16A1 Rifle and .45 Cal Pistol Marksmanship Training Evaluation

A 1980 report from the Army Research Institute for the Behavioral and Social Sciences. The FORSCOM/US Army Marksmanship Unit M16A1 rifle and .45 cal pistol training evaluation was conducted to evaluate two candidate programs of instruction (POI) for rifle and pistol training at the field unit level. Performance and attitudinal measures were collected from soldiers of the 1/504th Infantry Bn (Airborne) who participated in the rifle and pistol training programs. The subjects were all males from a combat ready battalion. Soldiers in both the rifle and pistol programs who received FULL-AMU treatment performed better and expressed greater confidence in training than did those receiving the PART-AMU, or abbreviated training. Both performed better and expressed greater confidence in training than those in standard annual qualification training treatments. The study finds that a unit using the AMU POIs for rifle and pistol training could elect to use the FULL or PART POIs based on available training time and resources and expect improved performances over current standard procedures. If time is available the FULL POIs (rifle and pistol) would provide the greatest performance increases in terms of number of soldiers qualified and level of qualification.

Adequacy of M16A1 Rifle Performance and Its Implications for Marksmanship Training

A 1980 Mellonics Systems Development, Division of Litton Systems report. This document records firing test results for typical M16A1 rifles, providing data for simplified and improved marksmanship training procedures. Sixty rifles were selected at random and subjected to bench-type serviceability checks and accuracy firing tests. Following initial testing, a representative sample (good, average and bad) of nine rifles was selected for the following tests: zero procedures, zeroing with the long range sight, trajectory, rimfire adapter, effects of barrel stress, firer error and firing by initial entry soldiers. This document was intended for marksmanship training developers and proponents of marksmanship hardware items.

Other Reports include:

Aerodynamic Characteristics of the 7.62 MM NATO Ammunition M-59, M-80, M-61, M-62 (1967)

Sensitivity Study of Rifle Gas Systems (1971)

Correlation of Breech Erosion Gage to Accuracy for M16A1 Rifle with Chrome Plated Barrel Bores (1975)

Projectile Engraving Mutations and Their Relationships to Accuracy of the M16A1 Rifle (1975)

External Barrel Temperature of the M16A1 Rifle (1975)

Study of Man-Weapon Reaction Forces Applicable to the Fabrication of a Standard Rifle Firing Fixture (1975)

Calibration of Breech Erosion Gage for 5.56mm Chrome-Plated Bores (1975)

Firing Shock Measurements on the M16 Rifle/M203 Grenade Launcher System (1976)

Evaluation of Lubricating Composites for the M16A1 Rifle (1976)

Bore Erosion and Accuracy of M16A1 Rifle (1977)

The disc contains a text transcript of all recognizable text embedded into the graphic image of each page of each document, creating a searchable finding aid. Text searches can be done across all files on the disc.


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