7.62x51mm Vs. 5.56x45mm

TITLE:

7.62 mm Versus 5.56 mm - Does NATO Really Need Two Standard Rifle Calibers CSC 1986 SUBJECT AREA General 7.62 mm Versus 5.56 mm - Does NATO Really Need Two Standard Rifle Calibers?

I. Purpose: To reestablish the 7.62mm NATO cartridge as the optimum rifle caliber ammunition for the U. S. and NATO. II. Problem: NATO recently adopted the 5.56mm as its second standard rifle caliber cartridge. As a result, the existing NATO standard, the 7.62mm, has been relegated to a secondary supporting role within NATO's armed forces. Although the selection of the 5.56mm was based on extensive testing, research, and documented battle performance, this intermediate power round is not the optimum ammunition and caliber for U. S. and NATO forces in the contemplated battlefields of the future. III. Discussion: Proponents of the intermediate power 5.56mm have continuously compared their smaller cartridge to the large full power 7.62mm. The results of these comparisons purportedly show the superiority of the smaller ammunition in the areas of penetration, lethality, weapon portability, and fire power. Careful examination of these tests and the touted advantages of the 5.56mm, however, shows that the 7.62mm is still potentially superior to the smaller round. For example, in the NATO tests, researchers have compared a modern, semi-armor piercing round of ammunition (5.56mm) against a standard ball cartridge (7.62mm) that has not been improved since its adoption in 1953. An improved 7.62mm NATO, using the same technology as the 5.56mm, would definitely out-perform the smaller cartridge. With respect to portability, second generation 7.62mm rifles are smaller, more compact, and very comparable to certain 5.56mm weapons. Concerning fire power, any full automatic fire with light assault rifles, even with the low-recoil 5.56mm, is not effective and only results in a waste of ammunition. In addition, new technological developments in body armor may soon defeat the penetration capability of the small 5.56mm. New developments in optical sighting equipment will soon increase battlefield engagement ranges and thereby exceed the long range accuracy capability of the smaller 5.56mm. The large case and projectile of the 7.62mm, however, are more than sufficient to accept significant improvements in penetration, lethality, and long range performance. This

will allow the 7.62mm to remain effective on future battlefields. IV. Conclusion: The 5.56mm will, at best, only be an interim NATO standard. Due to its small size, further improvements of the 5.56mm will be insufficient to keep up with the changing requirements of future battlefields. Overall, the older 7.62mm NATO is a better standard cartridge since it has the capacity and the flexibility to be significantly improved and thereby remain effective. V. Recommendations: The 7.62mm NATO cartridge should be developed with current technology to improve its penetration, lethality, and overall-performance. Modern weapons systems should be further developed to utilize the 7.62mm. No, NATO does not need two standard rifle calibers. Major Vern T. Miyagi

Conference Group 6 RESEARCH PAPER Title 7.62mm Versus 5.56mm - Does NATO Really Need Two Standard Rifle Calibers? Thesis Statement Although the selection of the 5.56 x 45mm cartridge was based on extensive testing, research, and documented battle performance, this intermediate power round is not the optimum ammunition and caliber for U. S. and NATO forces in the contemplated battlefields of the future. I. Significance of the Controversy A. Thesis statement B. Method of analysis II. Evolution of the Intermediate Power Cartridge Concept A. Germany B. Soviet Union C. United States III. Development of the Two Standard NATO Cartridges A. 7.62 x 51mm NATO B. 5.56 x 45mm NATO C. NATO trials D. Concepts of employment - NATO IV. Comparison of the 7.62mm With the 5.56mm A. Physical characteristics and ballistics B. Penetration C. Portability and weight D. Firepower V. Analysis A. Problems with the NATO comparisons and tests

B. Factors not considered in the NATO tests C. Effects of technological advances in optical sights and body armor on the initial intermediate power concepts D. Potential for improvement and development 5.56mm v. 7.62mm E. Lethality of improved round is reduced F. Potential ineffectiveness on NATO scenario battlefields 7.62 mm Versus 5.56 mm - Does NATO Really Need Two Standard Rifle Calibers? On 28 October 1980, after more than four years of extensive testing at the German Infantry School at Hammelburg, Federal Republic of Germany, the NATO Small Arms Test Control Commission (NSMATCC) approved the standardization of a second rifle caliber cartridge. The cartridge selected was the intermediate power 5.56 x 45mm (.223 Caliber) and the improved Belgian version, the SS109, was selected as the basis for standardization.1 As a result, NATO now has two standard rifle caliber cartridges, the full power 7.62 x 51mm NATO (.308 Caliber), in service since 1953, and the new intermediate power 5.56 x 45mm NATO adopted in 1980. Although the selection of the 5.56 x 45mm cartridge was based on extensive testing, research, and documented battle performance, this intermediate power round is not the optimum ammunition and caliber for U. S. and NATO forces in the contemplated battlefields of the future. Let's examine the concept of intermediate power rifle ammunition, the evolution of the two standard NATO rifle cartridges, their advantages and disadvantages, and discuss why the older, full power 7.62 x 51mm NATO cartridge can better satisfy the present and future tactical needs of the individual NATO rifleman. The concept of intermediate power rifle cartridges began in Germany prior to World War II. The standard German rifle cartridge used since 1888 was the full power 7.92 x 57mm which propelled a 198 grain bullet at a muzzle velocity of 2,550 feet per second (fps) or 773 meters per second (mps). Comprehensive studies of the actual distances over which rifle fire was employed and of the marksmanship capabilities of the average German infantryman, especially during the heat of battle, convinced German researchers that a smaller, substantially less-powerful, and lighter cartridge would be more than adequate. In addition, the adoption of smaller intermediate power cartridges would allow the development of shorter and lighter rifles, the ability to carry more

rounds of ammunition, and the enhancement of accuracy due to lighter recoil. German research for a new intermediate round commenced in 1934, and in 1938 a new intermediate cartridge was adopted and designated the 7.9 mm Infanterie Kurz Patrone (7.9 mm Kurz). This cartridge propelled a small 125 grain bullet at a relatively moderate muzzle velocity of 2,100 fps (636 mps), Paralleling the evolution of the 7.9 mm Kurz was the development of a new, compact, select-fire rifle chambered for the new ammunition. In 1940, two designs were accepted for field testing and were extensively used on the Russian front. The final version "Sturmgewehr" or assault rifle, the MP43, was adopted in 1943 and significant numbers were produced prior to the end of the war. This weapon utilized a thirty round magazine and could provide both semiautomatic and full automatic fire. Although the MP43, with a fully loaded thirty round magazine, was more than three pounds heavier than the standard bolt-action Kar 98k rifle, the new weapon's performance in the field was excellent due to the terrific firepower now available to the German infantryman.2 The effectiveness of the new rifle and ammunition did not go unnoticed by Soviet forces, especially since they were the first recipients of its firepower. Captured rifles and ammunition were carefully studied, and in 1943 an intermediate power cartridge designed by Soviet engineers, N. M. Elizarov and B. V. Semin, was adopted by the Soviet Union. This cartridge was designated the 7.62 x 39mm Model 1943 and consisted of a 125 grain bullet with a muzzle velocity of 2,200 fps (667 mps). Due to wartime materiel and production shortages, the first weapon designed to use this new ammunition, the SKS Carbine, was not adopted until 1946. One year later, the famous AK-47, designed by M. Kalashnikov, was formally adopted by the Soviet armed forces.3 In 1974, a product improved version of the same basic design, the AKS74 rifle, was adopted by the Soviet army. The AKS74 is chambered for a new 5.45 x 39mm (.221 Caliber) cartridge, very similar to our own 5.56 x 45mm NATO. The Soviets also adopted, at the same time, a new 5.45mm squad automatic weapon, called RPK74.4 These recent changes in Soviet small arms development are very important because they closely parallel the small arms concepts of the U. S. and NATO. Like the Germans and Soviets, the U. S. also experimented with intermediate power cartridges during World War II. Designed as a replacement for the pistol and submachine gun during World War II, the U. S. .30 Caliber M1 and M2 carbines fires lighter and smaller .30 caliber

cartridges (7.62 x 33mm). This cartridge propelled a small round-nosed 115 grain bullet at an initial velocity of 1,970 fps (597 mps). The carbine and its cartridge, however, were designed for issue only to officers, noncommissioned officers, service troops, and members of heavy weapons crews. The carbine, with its intermediate power cartridge, was never designed to replace the M1 Garand and its full power .30 Caliber M2 (30-06) ammunition. Over six million carbines were produced during World War II and the Korean War. Although the carbines were light, compact, had a select fire capability (M2 model), and utilized magazines with capacities of thirty or fifteen rounds, these weapons eventually came to be unpopular with U. S. troops due to the limited range and inadequate stopping power of the carbine ammunition. Soon after the Korean War, the U. S. M1 and M2 Carbines were retired from service.5 Such was the evolution of the intermediate power cartridge concepts in Germany, the Soviet Union, and the United States during the 1940's. Lets now take a look at the development of the 7.62 x 51mm NATO and the 5.56 x 45mm NATO during the 1950's and 1960's The first standard NATO cartridge, the 7.62 x 51mm NATO, was developed by the United States as a successor to the .30 Caliber M2 round (30-06), which had served as the standard U. S. rifle cartridge since 1906. The .30 Caliber M2 cartridge propelled a 150 grain projectile at a muzzle velocity of 2,800 fps (848 mps)and served the U. S. very effectively in the 1903 Springfield and M1 Garand service rifles, the Browning automatic rifle, and the heavy and light models of the Browning machine guns. Although the M1 Garand was very effective and highly praised during its service as the standard U. S. rifle in World War II and Korea, many infantrymen desired a lighter weapon with greater ammunition capacity and a select-fire capability.6 Many soldiers attempted to use the M2 carbine as a replacement for the M1 Garand, but this proved unsatisfactory due to the inadequate power of the carbine ammunition. In September 1945, after conducting preliminary tests to improve the M1 rifle, the U. S. Ordnance Technical Committee turned its attention to the development of a new and lighter rifle cartridge that would replace the .30 Caliber M2 round. This interest in a new cartridge was influenced by the battlefield success of the German 7.9mm Kurz, and Soviet adoption of their Kalashnikov light assault rifles using the new 7.62 x 39mm Model 43 intermediate power ammunition. As the development of the new U. S. service rifle cartridge progressed, however,

traditionalism took hold as U. S. Army participants began to feel that the intermediate power ammunition, used by the Soviets and the Germans, were too limited in their effective combat ranges and power to satisfy U. S. infantry requirements. The result was a compromise. The Ordnance Technical Committee came up with a shortened version of the old .30 caliber M2 cartridge. This new cartridge, designated the 7.62 x 51mm T65, was not an intermediate power round. Although shorter by a half inch than the old Caliber .30 M2 round, it still propelled a 147 grain bullet at a muzzle velocity of 2,800 fps (848 mps) -- essentially identical to the old .30 Caliber M2 round. Newly developed ball powder allowed the use of smaller cartridge case to produce pressures and velocities identical to the old full power .30 Caliber M2 round.7 Final U. S. adoption of the new 7.62 x 51mm T65 cartridge depended upon the acceptance of the new round by members of the NATO alliance. During the early 1950's, the British conducted their own tests to determine the optimum rifle ammunition for their troops. They concluded that a . 280 Caliber (7 mm) cartridge was the ideal rifle caliber. The proposed British cartridge was a true intermediate power cartridge based on German experience and Soviet developments. In 1953, after much political debate, the U. S. 7.62 x 51mm T65 round was finally adopted by the NATO Alliance as its standard rifle caliber cartridge. In 1957, after numerous trails, the U. S. finally adopted the M14 rifle as its new standard 7.62mm NATO caliber service rifle. The other members of NATO adopted either the German G3 or the Belgian FN FAL as their standard 7.62mm NATO caliber service rifles.8 The 5.56 x 45mm cartridge and the M16 rifle was originally developed and unilaterally adopted by the United States in 1963 for initial employment in Southeast Asia. A resurgence of U. S. interest in intermediate power rifle cartridges developed soon after the 7.62 x 51mm NATO was adopted in 1953. A series of tests, commissioned by the U.S. Army and conducted by the Operations Research Organization (ORO), concluded that the rifle was seldom used effectively by U. S. troops at ranges in excess of 300 meters (330 yds). This conclusion was based on studies of actual battles involving U. S. soldiers. According to the ORO studies, the inability of U. S. soldiers to effectively engage targets beyond 300 meters was due to their inability, under battle conditions, to see and identify targets beyond that range.9 The ORO studies, however, failed to consider whether the enemy targets were behind

heavy brush, or barriers such as sandbags, dirt berms, and coconut logs when fired on by U. S. soldiers. The study assumed that there was nothing between the firer and the target to impede the flight of the rifle projectile. Concurrently, ballistic experiments, conducted as part of the U. S. Army Project Caliber, demonstrated the small high velocity bullets, ranging in caliber from .222 to .257 inches and weighing only 40 to 55 grains, were very effective at ranges up to 400 meters.10 As a result of these studies, the Continental Army Command (CONARC) asked selected commercial arms organizations to develop high velocity .223 Cal (5.56mm) ammunition and light weight assault rifles chambered for them. After extensive testing of candidate weapons and ammunition submitted by various manufacturers, CONARC selected the AR15 rifle and the 5.56 x 45mm ammunition, both developed by Eugene Stoner of the Armalite Division of the Fairchild Aircraft Engine Corporation. The 5.56 x 45mm cartridge was derived from the .222 Remington and .22 Hornet commercial cartridges used by small game hunters throughout the United States. After some modifications for military use, the AR15 and its 5.56 x 45mm, cartridge were accepted by CONARC and designated as the M16 and the M193, respectively.11 The M193 cartridge, as finally accepted by CONARC, propelled a small 55 grain bullet at an initial velocity of 3,180 fps (964 mps) through the standard 20 inch barrel of the M16. Test weapons and ammunition were sent to Southeast Asia in 1962 for combat field analysis. The reports from both U. S. and allied forces were very good and consequently, in 1963, Secretary of Defense McNamara ordered the cessation of M14 production and announced the purchase of 85,000 M16 rifles for the Army and 19,000 for the Air Force. Subsequent performance of the M16 in Vietnam was marred by frequent jamming caused by improper and insufficient maintenance in the field. Performance quickly improved as chrome barrels and chambers were used in the newer M16A1 model, and proper maintenance procedures were employed by troops in the field. The U. S. finally had adopted an intermediate power rifle cartridge and a true light-weight assault weapon to use it.12 The adoption of the 5.56 x 45mm cartridge and the M16 rifle put the U. S. into the situation of having two standard service rifles. The initial U. S. Army employment concept called for the issue of the M16 to special operations and airborne troops, and to troops in Southeast Asia. The M14 would still be issued to troops stationed in Europe of assigned to NATO.13 This initial concept proved

to be logistically impractical and, eventually, all U. S. troops were issued the new M16 rifle and 5.56 x 45mm ammunition. Based on the overall success of the 5.56mm ammunition in Southeast Asia, after the initial problems with the M16 were solved, other nations began to produce assault type rifles using the U. S. 5.56 x 45mm ammunition. In order to standardize the use and procurement of 5.56mm ammunition among member nations, NATO commenced formal adoption trials for a second small rifle caliber cartridge in 1976. The Belgian product-improved version of the U. S. M193 5.56 x 45mm cartridge was adopted by the alliance in 1980. The current NATO concept of employment calls for the issue of the 5.56mm weapons to individual riflemen, members of crew-served weapon teams, support troops, and officers and NCO's. The current NATO concept also includes the development and adoption of a squad automatic weapon (SAW) in 5.56 x 45mm NATO caliber. The goal of NATO small arms employment is to ensure ammunition interchangeability at the basic infantry squad level. The full power 7.62 x 51mm NATO remains the standard ammunition for the heavier beltfed medium machine guns (M60, MG3, and FN MAG) employed with infantry weapons squads, weapons platoons, and as vehicle mounted support weapons.14 In addition, specialized sniper weapons still employ the longer ranged 7.62 x 51mm NATO. The foregoing paragraphs reviewed the evolution of the Intermediate power cartridge concept, documented the development of the two standard NATO cartridges, and discussed the current concept of employment within the NATO alliance. Let's now compare the two cartridges, examine their strengths and weaknesses, and analyze why the 7.62 x 51mm NATO is a better rifle cartridge in the long run for the U. S. and NATO (Table I). The current production 7.62 x 51mm NATO ball cartridge has remained unchanged since its adoption by NATO in 1953. As typified by the U. S. M80 ball and the Belgian M77 ball, this cartridge propels a 147-grain cupronickel-jacketed lead bullet at a muzzle velocity of 2,800 fps (848 mps). Total cartridge length and weight are 2.80 inches and 386 grains, respectively.15 Utilizing a standard 22-inch barrel with a rifling twist of one turn in twelve inches (M14 rifle), the maximum effective range of the 7.62 x 51mm ball cartridge is listed as 620 meters (682 yds). The U. S. M80 and the Belgian M77 ball projectiles can penetrate the standard NATO 3.45 mm (.14 inch) thick steel plate up to a range of 620 meters, and can penetrate one side of the

U. S. steel helmet up to a range of 800 meters (880 yds).16 In barrier and fortification penetration tests, the 147 grain ball projectile can consistently penetrate two test building blocks.17 The SS109 5.56mm NATO cartridge is a second generation intermediate power round developed with 1970's technology. It is significantly more powerful and effective than the U. S. M193 5.56mm ball round originally used with the M16 rifle. The new SS109 cartridge propels a heavier 62-grain semi-armor piercing projectile at an initial velocity of 3,050 fps (924 mps).18 The improved projectile contains a 10-grain .182 caliber hardened steel penetrator that ensures penetration at longer ranges. Total cartridge length and weight are 2.26 inches and 182.0 grains, respectively. The increased length and weight of the new SS109 projectile requires a faster rifling twist of one turn in seven inches to fully stabilize the new projectile in flight.19 The predecessor M193 5.56mm, which used a projectile weighting only 55 grains, was only marginally stabilized with a slower rifling twist of one turn in twelve inches. The new projectile can penetrate the standard NATO 3.45mm steel plate up to a range of 640 meters (704 yds) and one side of the U. S. steel helmet up to a range of 1,300 meters (1430 yds).20 In tests of barrier and fortification penetration however, the steel penetrator of the SS109 could not pierce any of the test building blocks.21 The primary advantages of the intermediate power 5.56 x 45mm NATO cartridge are summarized as follows: (1) the penetration and power of the SS109 version are superior to the 7.62mm NATO and more than adequate for the 300-meter average combat range documented in actual battle (ORO studies): (2) the lower recoil generated by the 5.56mm cartridge allows more control during full automatic fire and therefore provides greater firepower to the individual soldier; (3) the lesser weight of the 5.56mm ammunition allows the individual soldier to carry more ammunition and other equipment; (4) the smaller size of the 5.56mm ammunition allows the use of smaller, lighter, and more compact rifles and squad automatic weapons and; (5) the lethality of the 5.56mm projectile is greater than the 7.62mm projectile at normal combat ranges, due to the tendency of the lighter projectile to tumble or shatter on impact. In summary, the 5.56mm NATO provides greater firepower and effectiveness than the larger and heavier 7.62mm NATO. This concept of more for less appears very

convincing, however upon careful analysis, this idea loses its credibility. Let's examine each of the advantages of the 5.56mm NATO, compare them to the qualities of the larger 7.62mm NATO, and discuss some critical factors not addressed by proponents of the smaller cartridge. The penetration results obtained by the NSMATCC with the 5.56mm SS109 cartridge are impressive. The SS109 can penetrate the 3.45mm standard NATO steel plate to 640 meters, while the 7.62mm ball can only penetrate it to 620 meters. The U. S. steel helmet penetration results are even more impressive as the SS109 can penetrate it up to 1,300 meters, while the 7.62mm ball cannot penetrate it beyond 800 meters. These comparisons however, do not consider the fact that the SS109 uses a semi-armor piercing, steel-cored projectile, while the 7.62mm ball uses a relatively soft anti-personnel, lead-cored projectile. A semi-armor piercing 7.62mm caliber projectile, using second generation technology as the SS109, would easily out-perform the smaller SS109 projectile in penetration tests at all ranges.22 With respect to barrier and fortification penetration tests, the 7.62mm ball projectile can consistently penetrate two test building blocks, while the SS109 semi-armor piercing projectile cannot penetrate a single block. In light of these considerations, the idea of SS109 penetration superiority over the 7.62 x 51mm is not valid. The concept that greater firepower can be achieved by providing as much infantrymen with a full automatic fire capability is not realistic. Battle experience has shown that full automatic fire from light assault rifles is largely ineffective and only results in the expenditure of large quantities of ammunition. Even with the lower recoil generated by 5.56mm ammunition, automatic fire dispersion is still too large to be effective.23 Fire power is normally equated with maximum "steel" on target, not with maximum steel in the general direction of the target. Full automatic fire with the 5.56mm NATO just as wasteful and Confirming this view is the fact that second generation assault rifles, such as the U. S. M16A2 and Belgian FN FNC, are not employing a 3-shot burst control in lieu of a full automatic capability.24 With this burst control feature, a thirty round magazine produces only ten bursts. Do we need thirty rounds to successfully hit and incapacitate ten enemy targets? Even with 3-shot burst control and the lower impulse of the 5.56mm ammunition, shot dispersion is still too large to be effective. Perhaps a single wellaimed 147 grain 7.62mm bullet would have more effect than

three rounds of 5.56mm fired in the burst control mode. As a result, the lower recoil and impulse of the 5.56mm ammunition does not provide greater fire power since full automatic fire from an individual assault rifle is largely ineffective and only wastes ammunition. A great deal of emphasis has been placed, during the development of intermediate power ammunition, on ammunition weight. It is a fact that 5.56-mm NATO ammunition weight only 47% as much as 7.62 mm NATO ammunition. This weight reduction advantage however, comes with a corresponding disadvantage in the power and effectiveness of the ammunition. The 5.56mm NATO cartridge was originally derived from commercial small game and varmint cartridges used by hunters throughout the United States. In most States, the .223 Remington cartridge, the commercial version of the 5.56 x 45mm NATO, is outlawed for use against deer-sized or larger game. This restriction even includes the explosive hollow-point versions using 68-grain projectiles. Years of hunting experience has shown that the small 5.56 x 45mm cartridge is incapable of consistently stopping deer-sized or larger game. Consequently, this cartridge is limited to game such as woodchucks, gophers, turkeys, and prairie dogs.25 Is this cartridge really adequate for human-sizes targets? Soldiers can definitely carry more 5.56mm ammunition, but will they be carrying more effective ammunition? As a case in point, battle experience in the Philippines, between government troops (armed with the 5.56mm M16A1) and Communist rebels (armed with vintage .30 Caliber M1 Garand and Browning automatic rifles), has shown that the greater penetration capability of the older full power cartridge gave the rebels superior effective firepower.26 Another stated advantage of the smaller 5.56mm NATO cartridge concerns the employment of shorter and lighter weapons. Current versions of the Israeli Galil and FN FAL Paratroop rifles, however, both in 7.62mm caliber, weigh only nine to ten pounds fully loaded with twenty-round magazines. These 7.62mm NATO weapons also have shorter barrels and folding stocks that make them very compact. The new U. S. M16A2 and the new Belgian FN FNC, both second generation 5.56mm NATO assault rifles, weigh approximately eight27 and ten pounds,28 respectively, when fully loaded with thirty-round magazines. The purported reductions in weight and improvements in compactness are really not significant. The lethality of the original M193 5.56mm projectile is awesome, at ranges under 200 meters, due to the tendency

of the marginally stable 55-grain bullet to tumble or shatter on impact with any target. Lethality of the M193 5.56mm projectile beyond 200 meters, however, falls very sharply as range increases and velocity decreases.29 The lethality of the new SS109 5.56mm projectile on the battlefield is questionable. The SS109 projectile is longer and heavier than the M193 projectile and is more stabilized in flight with the faster rifling twist used in second generation assault rifles. The emphasis, in the development of the SS109 projectile, was to increase stability and therefore penetration at longer ranges. The increased flight stability of the new SS109 projectile does effectively enhance penetration at longer ranges, but this same stability reduces the projectile's tendency to tumble or shatter upon target impact.30 As a result, the emphasis on penetration in the new SS109 projectile may result in a sharp decrease in lethality, as compared to its predecessor M193 cartridge. The adoption of intermediate power ammunition by a large number of countries was based on the limited ability of the average soldier to discern and identify targets under battle conditions. The U. S. Army's ORO studies during the 1950's, confirmed these ideas and established 300 meters as the practical range limit for rifles under battle conditions. The ORO studies, however, failed to consider the technological advances of the 1970's and 1980's in the area of optical weapons sights. The battle proven British Trilux optical sight, with a four power magnification, has been employed by the British effectively on their 7.62mm FN FALs for many years.31 Their newly adopted 5.56mm NATO individual weapon, the SA 80, utilizes a built-in version of the Trilux called the SUSAT.32 The Austrian developed 5.56mm NATO assault rifle, the AUG, employs a 1.5 power optical sight built in to the weapon's carrying handle.33 The U. S. Army is also considering a new optical sight for its version of the M16A2. These improved optical sights greatly increase the average soldier's ability to see and identify enemy targets at longer ranges. As the soldier's ability to engage targets beyond the 300 to 400 meter NATO limitation increases, the long range accuracy limitations of the 5.56mm SS109 projectile will become evident. The 62-grain 5.56mm NATO projectile is significantly more affected by weather conditions than the heavier projectile of the 7.62mm NATO. For example, at 400 meters the required windage adjustment for a 10 mph crosswind for the SS109 cartridge is approximately 9 clicks into the wind using the M16A2

sights. Under the same conditions, the required windage adjustment for the 7.62mm NATO cartridge is only 4 clicks using the M14 sights. The larger sight adjustment, required for the SS109 projectile, produces a greater margin of error that increases as distance increases. As the potential rifle engagement distances increase, due to improvements in optical sights, the limited accuracy potential of the small 5.56mm NATO projectile will severely limit any benefits that may be derived from such optical improvements. New technological developments in body armor and individual protection, such as kevlar and other lightweight ceramic and composite armor, may soon defeat the penetration capability of the small 5.56mm SS109 projectile. For example, the new Soviet 5.45 x 39mm ammunition cannot now penetrate a relatively light 5.8 pound flak jacket composed to Kevlar and a 4.8mm (.19 inch) sheet of hardened steel plate, even at point blank range.34 The SS109 however, with its steel penetrator still has this capability. The primary question is how long will the 5.56mm SS109 retain this capability? As a second generation intermediate power cartridge, further improvements in the small 5.56mm SS109 may not be sufficient to defeat new technological developments in body armor. The 5.56mm SS109 projectile is too small for much significant improvement. It has also been maintained, by intermediate caliber proponents, that the 5.56 x 45mm cartridge has proven itself in battle since its adoption by the U. S. in 1963. In most of these conflicts, however, the 5.56mm weapons were employed against opponents armed with Soviet weapons also using intermediate power ammunition. When the 5.56mm weapon comes up against an opponent armed with weapons using full-power ammunition, such as in the Philippine example cited previously, the 5.56mm armed soldier finds himself at a severe disadvantage. The "obvious" advantages of the 5.56 x 45 mm NATO are not obvious at all. The SS109 is a definite improvement over the first generation M193 cartridge however, at best it will serve only as an interim standard. As technological improvements in optical sights extend the practical engagement distances for rifle fire, and as improvements in body armor require greater and greater power from the rifle cartridge, the SS109 and other 5.56mm caliber ammunition will have to give way to improve and more powerful ammunition, such as the 7.62mm NATO. The 7.62 x 51mm NATO has not been improved or modified since

its adoption by NATO in 1953. This larger cartridge has a greater capacity for growth and technological improvement and should be developed to its potential now. The large size of the 147-grain 7.62 mm projectile is more than sufficient to incorporate significant improvements in lethality and penetration. We must capitalize on the Soviet trend toward their 5.45mm caliber weapons by improving our full power 7.62mm NATO ammunition and designing better and more efficient weapons to use it. We have a chance to totally outclass Soviet small arms in the area of individual and squad weapons. Let's do it by upgrading the existing 7.62 mm NATO to its full potential. During the years just prior to World War II, the Imperial Japanese Army replaced their 6.5mm (.256 Caliber) rifle ammunition with a 7.7mm (.303 Caliber) cartridge due to the smaller round's poor lethality and its inability to penetrate barriers and effectively stop enemy troops. During the same period, the Italians replaced their 6.5mm rifle ammunition with a 7.35mm (.301 Caliber) cartridge for the same reasons. Let’s learn from their examples and concentrate now on the development and improvement of the 7.62mm NATO round. No, NATO does not need two standard rifle calibers. Footnotes 1Edward C. Ezell, Small Arms of the World, 12th Revised Edition (Harrisburg: Stackpole Books, 1983) Pp. 57,61. 2IBID, Pp. 514 - 519. 3IBID, Pp. 34 - 35. 4Andrew C. Tillman, "IDR Test Fires the AKS74," International Defense Review, October 1983, Pp. 1427 - 1428. 5Edward C. Ezell, Small Arms of the World, 12th Revised Edition (Harrisburg: Stackpole Books, 1983) Pp. 779 - 784. 6Edward C. Ezell, The Great Rifle Controversy (Harrisburg: Stackpole Books, 1984) P. 41. 7IBID, Pp. 57 - 61. 8IBID, Pp. 92 - 103. 9Norman Hitchman, Operational Requirements For An Infantry Hand Weapon (Chevy Chase: Operations Research Office - The John Hopkins University Publications, 1952) Pp. 2 - 3. 10William C. Benjamin Jr. and Joseph Dubay, The Effect of Rifle Caliber and Muzzle Velocity on Experimental Probabilities of Hitting as Obtained from Project Caliber (Aberdeen: Ballistic Research Laboratories Report No. 964, 1955) Pp. 29 - 30. 11Edward C. Ezell, The Great Rifle Controversy (Harrisburg: Stackpole Books, 1984) P. 172. 12IBID, P. 192 13IBID, P. 195. 14Herman Van Assche, "Small Arms and Their Ammunition - The

NATO Competition, "NATO's Fifteen Nations, August - September, 1981, Pp. 92-93. 15R. T. Huntington, Small-Caliber Ammunition Identification Guide Vol 1 (Army Material Development and Readiness Command, Foreign Service and Technology Center, June 1978) Pp. 32. 16Pierre Crevecoeur, "The Belgian SS-109 Round - Baseline for NATO's Second Caliber Ammunition," International Defense Review, March 1981, P. 302. 17Andrew C. Tillman, "IDR Tests the M16A2 Assault Rifle," International Defense Review, September 1984, P. 1353. 18IBID, P. 1353 19Edward C. Ezell, Small Arms of the World, 12th Revised Edition (Harrisburg: Stackpole Books, 1983) Pp. 59-60. 20Pierre Crevecoeur, "The Belgian SS-109 Round - Baseline for NATO's Second Caliber Ammunition," International Defense Review, March 1981, P. 302. 21Andrew C. Tillman, "IDR Tests the M16A2 Assault Rifle," International Defense Review, September 1984, P. 1353. 22Edward C. Ezell, "NATO Small Arms Debate," International Defense Review, March 1981, P. 297. 23Andrew C. Tillman, "IDR Tests the M16A2 Assault Rifle," International Defense Review, September 1984, P. 1352. 24Edward C. Ezell, Small Arms of the World, 12th Revised Edition (Harrisburg: Stackpole Books, 1983) Pp. 64, 255. 25Jack S. Chase, "Are We Arming American Soldiers to Flight an Army of Woodchucks?" Armed Forces Journal International, October 1981, Pp. 24 - 26. 26Interview with LTC Wenceslao Cruz, Philippine Marine Corps, March 3, 1986. 27Andrew C. Tillman, "IDR Tests the M16A2 Assault Rifle," International Defense Review, September 1984, P. 1351. 28Edward C. Ezell, Small Arms of the World, 12th Revised Edition (Harrisburg: Stackpole Books, 1983) P. 255. 29Andrew C. Tillman, "IDR Test the M16A2 Assault Rifle," International Defense Review, September 1984, P. 1353. 30Edward C. Ezell, Small Arms of the World, 12th Revised Edition (Harrisburg: Stackpole Books, 1983) P. 60. 31W. J. G. Hancock, "The TRILUX Infantry Sight Unit," International Defense Review, April 1973, Pp. 113 - 114. 32Edward C. Ezell, Small Arms of the World, 12th Revised Edition (Harrisburg: Stackpole Books, 1983) Pp. 298 - 301. 33IBID, P. 223. 34Andrew C. Tillman, "IDR Tests the AK74," International Defense Review, October 1983, Pp 1429 -1430. 35Edward C. Ezell, Small Arms of the World, 12th Revised Edition (Harrisburg: Stackpole Books, 1983) P. 603. Bibliography 1.

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