7.62×51mm NATO

During the 1940s, the .300 Savage became the basis for experiments on behalf of the U.S. Military that resulted in the development of the T65 series of experimental cartridges. The original experimental case design by the Frankford Arsenal was designated the T65 and was similar to the .300 Savage case, but with less taper. The experimental cases were made from standard .30-06 Springfield cases which gave a little less capacity than standard .300 Savage cases because the Frankford Arsenal cases had slightly thicker case walls. The later T65 iterations were lengthened compared to the original T65 case and provided a ballistic performance roughly equal to the U.S. military .30-06 Springfield service cartridge. Over forty years of technical progress in the field of propellants allowed for similar service cartridge performance – firing a 147 grains (9.53 g) bullet at 2,750 ft/s (838 m/s) with 2,468 ft⋅lbf (3,346 J) muzzle energy – from a significantly shorter, smaller case with less case capacity.[5][6] The eventual result of this competition was the T44 rifle.

When the United States developed the T65 cartridge, the British military took a different route. They had spent considerable time and effort developing the intermediate-power .280 British (7 mm) cartridge with an eye towards controllable fully automatic fire. The U.S. held to its desire not to reduce the effectiveness of individual aimed shots. The American philosophy was to use automatic fire for emergencies only and continue to use semi-automatic fire the majority of the time. After considerable debate, the Canadian Army announced they would be happy to use the .280 but only if the U.S. did as well. It was clear the U.S. was not going to use the .280 British. The British did start introducing the .280 British along with the bull-pup Rifle No. 9, but the process was stopped in the interests of harmonization across NATO. The T65E5 (7.62×51mm) was chosen as NATO's standard cartridge in 1954.

Winchester saw a market for a civilian model of the late T65 series designs and introduced it in 1952, two years prior to the NATO adoption of the T65E5 experimental cartridge iteration under the 7.62×51mm NATO designation in 1954. Winchester branded the cartridge and introduced it to the commercial hunting market as the .308 Winchester. The dimensions of .308 Winchester are almost the same as 7.62×51mm NATO. The chamber of the former has a marginally shorter headspace and thinner case walls than the latter due to changed specifications between 1952 and 1954. This allows 7.62×51mm NATO ammunition to feed reliably in rifles chambered for .308 Winchester, but can cause .308 Winchester ammunition cases to rupture when fired in rifles chambered for 7.62×51mm NATO.

Comparison of 7.62mm NATO, 5.56mm NATO and 9mm NATO

Service rifle cartridges loaded with projectiles: (left to right) 7.62×54mmR, 7.62×51mm NATO, 7.62×39mm, 5.56×45mm NATO, 5.45×39mm

The T44 rifle was adopted as the M14 rifle in 1957. Around the same time Britain and Canada adopted the Belgian FN FAL (L1A1 SLR British) as the L1 followed by the West German army designated as the G1. The Germans soon transitioned to a modified version of the Spanish CETME rifle by Heckler & Koch that was adopted as the G3. With all of these firearms, it was clear that the 7.62×51mm NATO could not be fired controllably in fully automatic because of recoil. Both the M14 and FAL were later modified to limit fully automatic selection through semi-automatic versions or selector locks. Efforts were also made to improve control with bipods or heavier barrels.

While this was going on, the U.S. Project SALVO concluded that a burst of four rounds into a 20-inch (51 cm) circle would cause twice the number of casualties as a fully automatic burst by one of these rifles, regardless of the size of the round. They suggested using a much smaller, .22 caliber, cartridge with two bullets per cartridge (a duplex load), while other researchers investigated the promising flechette rounds that were lighter but offered better penetration than even the .30-06.

When the M14 arrived in Vietnam, it was found to have a few disadvantages. The rifle's overall length was not well suited for jungle warfare. Also, the weight of 7.62×51mm NATO cartridges limited the total amount of ammunition that could be carried in comparison with the 7.62×39mm cartridge of the Type 56 and AK-47 rifles, with which the Vietcong and North Vietnamese Army soldiers were equipped. In addition, the originally issued wooden-stocked versions of the M14 were susceptible to warping from moisture in tropical environments, producing "wandering zeroes" and other accuracy problems, which caused the adoption of fiberglass stocks.

Fighting between the big-round and small-round groups reached a peak in the early 1960s, when test after test showed the .223 Remington (M193 5.56×45mm) cartridge fired from the AR-15 allowed an eight-soldier unit to outgun an 11-soldier unit armed with M14s at ranges closer than 300 meters. U.S. troops were able to carry more than twice as much 5.56×45mm ammunition as 7.62×51mm NATO for the same weight, which allowed them an advantage against a typical NVA unit armed with Type 56-1s.

In 1964, the U.S. Army started replacing their M14s with M16s, incurring another series of complaints from the British. Regardless of the M14 having disadvantages in jungle warfare, 7.62×51mm NATO rifles stayed in military service around the world due to several factors. The 7.62×51mm NATO has proved much more effective than 5.56×45mm at long ranges, and has since found popularity as a sniping round. For instance, M14 variants such as the Mk 14 Enhanced Battle Rifle and M25 Sniper Rifle were utilized in the United States military as designated marksman and sniper rifles. Shorter, easier-to-handle 7.62mm rifles like the Heckler & Koch G3 stayed in service due to their accuracy, range, cartridge effectiveness and reliability.

M13 links reassembled to previously by a general-purpose machine gun fired 7.62×51mm NATO cartridge cases

Specialized loadings were created for 7.62×51mm NATO-chambered sniper rifles. They used heavier and more streamlined bullets that had a higher ballistic coefficient than standard ball rounds, meaning they shed velocity at longer ranges more gradually. Loss of velocity is important for accurate long-range shots because dropping from supersonic to transonic speeds disturbs the flight of the bullet and adversely affects accuracy. The standard M80 ball round weighs 147 gr and has a muzzle velocity 200 ft/s (61 m/s) faster than the M118LR 175 gr sniping round. However, the M80 drops to subsonic velocity around 900 m (980 yd), while the initially slower M118LR is supersonic out to 1,000 m (1,100 yd) due to its low-drag bullet.[8]

The 7.62×51mm NATO round nevertheless met the designers' demands for fully automatic reliability with a full-power round. It remained the main machine gun round for almost all NATO forces well into the 1990s, even being used in adapted versions of older .30-06 Springfield machine guns such as the Browning M1919A4 from the WWII era. The .303 British Bren gun was also subject to conversion to fire the 7.62×51mm NATO round, the converted weapon being reclassified as the L4 Light machine gun. These have been replaced to a considerable extent in the light machine gun role by 5.56×45mm weapons, such as the widespread use of the M249 SAW, but the 7.62×51mm NATO round is still the standard chambering for the minigun machine gun and most general-purpose machine guns such as the M60E4, FN MAG/M240, HK21, MG3, AA-52, Vektor SS-77, UKM-2000 and MG5 and flexible mountings such as helicopters, jeeps, and tanks. It is also commonly found in coaxial mount applications such as found in parallel with the main gun on tanks. The M80 7.62mm bullet type was also subject to 21st century ballistic studies.[9]

The U.S. Army developed an improved version of the M80 ball 7.62mm round, designated the M80A1. The M80A1 incorporates changes found in the M855A1 5.56 mm round. Like the M855A1, the M80A1 has better hard-target penetration, more consistent performance against soft targets, and significantly increased distances of these effects over the M80. The bullet is redesigned with a copper jacket and exposed hardened steel penetrator, eliminating 114.5 grains (7.4 g) of lead with production of each M80A1 projectile.[10] The M80A1 began fielding in September 2014.[11] The Army plans to replace both the M80A1 Enhanced Performance Round and M993 Armor Piercing round with the XM1158 Advanced Armor Piercing Round beginning in 2020.[12]

The U.S. Special Operations Command plans to begin fielding of the 6.5 Creedmoor cartridge in early 2019 to replace the 7.62 NATO round in semi-automatic sniper rifles. Tests determined that compared to the 7.62 NATO, the 6.5 Creedmoor doubles hit probability at 1,000 meters, increases effective range by nearly half, reduces wind drift by a third and has less recoil. The same rifles can use the new cartridge, as their similar dimensions allow the same magazines to be used and the weapon only requires a barrel change.[13][14]

• Cartridge, Caliber 7.62mm, NATO, Ball, F4 (Australia): 144-grain (9.3 g) 7.62×51mm NATO ball cartridge. Australian equivalent to U.S. M80 round. In service with the Australian Defence Force.

• SS77/1 (Ball): Designed by FN Herstal and adopted in 1957 by NATO. The Projectile weights 9.3g (143.5 gr), perforates a 3.5mm (NATO) mild steel plate at ≥ 550m and has a velocity at 25m of ± 833.5m/s.[21][22]
• L78 (Tracer): Designed by FN Herstal. The Projectile weights 8.9g (137.8 gr), does not perforates a 3.5mm (NATO) mild steel plate and has a velocity at 25m of ± 828m/s.[22]
• P80/1 (Armor Piercing): Designed by FN Herstal. The Projectile weights 9.8g (150.5 gr), perforates a 3.5mm (NATO) mild steel plate at ≥ 1100m and has a velocity at 25m of ± 823m/s.[22] The round is used in ballistic tests for the TR and VPAM body armor standards.[23]
• Blank: Designed by FN Herstal.[22]

• Patrone AB22, 7.62mm × 51, DM41, Weichkern ("soft-core", or "ball"), (West Germany): 7.62×51mm NATO ball cartridge; Berdan primed, copper-washed steel jacket. German equivalent to U.S. 7.62×51mm M80 round. Standard service round for the G3 battle rifle. It has a 3,800-metre (4,156 yd) long dangerous space when fired between a 5° and 10° angle.[24]
• Patrone AB22, 7.62mm × 51, DM111, Weichkern, (Germany): 147-grain (9.5 g) 7.62×51mm NATO ball cartridge, cupronickel-coated steel jacket. German equivalent to U.S. M80 round. In service with the German military. Known for severe fragmentation in human tissue due to its thin jacket, particularly around the cannelure.[25] It has a 4,200-metre (4,593 yd) long dangerous space when fired between a 5° and 10° angle.[26]
• Patrone, 7.62mm × 51, DM111A1, (Germany): Further development of the DM111. Retained "green" primer in place of lead acid primer and lead core capped with closure disc. Instead of steel jacket with gilding metal plating, the DM111A1 has a gilding metal jacket. Fragments in soft tissue, sometimes including the closure disc separating from the projectile base.[27]
• Patrone, 7.62mm × 51, DM111A2, (Germany): Further low pollutant development of the DM111A1.[28]
• Patrone, 7.62mm × 51, DM151, Hartkern ("hard-core", or "armor-piercing), (Germany):151-grain (9.8 g) 7.62×51mm NATO armor-piercing cartridge, tungsten carbide core, cupronickel-coated steel jacket. In service with the German military.[29] It has a 4,300-metre (4,703 yd) long dangerous space when fired between a 5° and 10° angle.[30]
• Patrone AM31, 7.62mm × 51, DM28A2, Manöver ("maneuver"), (Germany): Blanks, olive colored plastic with a brass base
• Patrone AM32, 7.62mm × 51, DM18A1B1, Übung ("practice"), (Germany): 10-grain (0.6 g) 7.62×51mm NATO plastic training cartridge, plastic case cartridge colored light blue with an light 10-grain plastic bullet which is fired with a high initial velocity. Non-corrosive, steel base with lead free primer. Developed from the Norwegian NM8 and NM127 short range practice rounds made by Bakelittfabrikken. Non-reloadable due to the plastic case.

The IMI 7.62×51mm long range match was optimized for the M24 SWS in use by the Israel Defense Forces. The combined sniper weapon system achieves accuracy of 0.5 minute of arc.

• IMI, 7.62mm × 51mm, long range match 175 gr[31] (Israel): 175-grain (11.3 g) 7.62×51mm NATO Match-grade round specifically designed for long-range sniping and optimized for the Israel Defense Forces sniper rifles, mainly the M24 SWS. It uses a 175-grain (11.3 g) Match King OTM-BT. An IDF M24 SWS with this round achieves accuracy of 0.5 MOA.[32] Produced at IMI Systems "Izhak" Ammunition Plant in Israel.

• Cartridge, grenade, L1A1 (United Kingdom): 7.62×51mm grenade-launching cartridge with one subvariant (L1A2).
• Cartridge, ball, L2A1 (United Kingdom): 7.62×51mm ball cartridge, with three subvariants (A2-A4).
• Cartridge, tracer, L5A1 (United Kingdom): 7.62×51mm tracer cartridge, designed to last out to 1,000 metres (1,100 yd). Four subvariants exist, with brighter ignition (A2), tracer reduced to 750 metres (820 yd) (A3), with a pistol powder charge (A4), and with improved ballistics (A5).
• Cartridge, ball, L42A1 (United Kingdom): 7.62×51mm ball cartridge, 155-grain (10.0 g) round
• Cartridge, ball, L44A1 (United Kingdom): 7.62×51mm ball cartridge, 144-grain (9.3 g) round

• Cartridge, caliber 7.62mm, NATO, ball, M59 (United States): 150.5-grain (9.8 g) 7.62×51mm NATO ball cartridge. A further development of the initial T65 cartridge. It has a long heavy bullet with a semi-armor-piercing iron or mild steel core and a gilded steel jacket. After the Vietnam War it was replaced by the M80 ball cartridge as the standard round. Data contained in TM 9-1005-298-12 mentions the approximate maximum range of 3,820-metre (4,180 yd) at 856.2-metre-per-second (2,809 ft/s) muzzle velocity.[33]
• Cartridge, caliber 7.62mm, NATO, high pressure test, M60 (United States): 7.62×51mm NATO test cartridge. The cartridge is not for field issue, but is used for proof firing of weapons during manufacture, test, or repair. The cartridge is identified by a stannic-stained (silvered) case.
• Cartridge, caliber 7.62mm, NATO, armor piercing, M61 (United States): 150.5-grain (9.8 g) 7.62×51mm NATO armor-piercing round, black cartridge tip. Data contained in TM 9-1005-298-12 mentions an approximate maximum range of 3,820-metre (4,180 yd) at 854.6-metre-per-second (2,804 ft/s) muzzle velocity.[34]
• Cartridge, caliber 7.62mm, NATO, tracer, M62 (United States): 142-grain (9.2 g) tracer cartridge, orange cartridge tip. Data contained in TM 9-1005-298-12 mentions an approximate maximum range of 2,340-metre (2,560 yd) at 856.2-metre-per-second (2,809 ft/s) muzzle velocity.[35]
• Cartridge, caliber 7.62mm, NATO, dummy, M63 (United States): The cartridge is used for practice in loading 7.62mm weapons for simulated firing to detect flinching of personnel during firing and for inspecting and testing the weapon mechanism. The cartridge is identified by six longitudinal corrugations (flutings) on the cartridge case. There is no primer and no vent hole in the primer pocket.
• Cartridge, caliber 7.62mm, NATO, grenade, M64 (United States): 7.62×51mm NATO grenade launching blank. The cartridge is identified by a rose-petal (rosette-crimp) closure of the cartridge case mouth and sealed with red lacquer. The cartridge provides pressure upon functioning to project rifle grenade to a desired target when using a grenade projectile adapter and dragon missile launch effect trainer (LET).
• Cartridge, caliber 7.62mm, NATO, ball, M80 (United States): 147-grain (9.5 g) 7.62×51mm NATO ball cartridge. The U.S. Army's Ballistic Research Laboratory measured a ballistic coefficient (G7 BC) of 0.200 and form factor (G7 i) of 1.105 for the M80 ball projectile.[36] Another source mentions a slightly higher ballistic coefficient (G7 BC) of 0.209.[37] Data contained in TM 9-1005-298-12 mentions the approximate maximum range of 3,930-metre (4,300 yd) at 856.2-metre-per-second (2,809 ft/s) muzzle velocity.[38]
• Cartridge, caliber 7.62mm, NATO, ball, enhanced projectile round, M80A1 (United States): 130-grain (8.4 g)[39] M80 lead free (LF) 7.62×51mm NATO ball cartridge.[40] 114.5-grain (7.4 g) of lead eliminated per M80A1 projectile.[10]
• Cartridge, caliber 7.62mm, NATO, blank, M82 (United States): 7.62×51mm NATO cartridge is used in rifles and machine guns equipped with blank firing attachments to simulate firing in training exercises and for performing military honors. The cartridge is identified by its double tapered (bottle nose) neck and absence of a bullet.
• Cartridge, caliber 7.62mm, NATO, ball, silent, XM115 (United States): Little is known of this round, but it was an attempt to quiet the round. Never adopted.
• Cartridge, caliber 7.62mm, NATO, match, M118 (United States): 173-grain (11.2 g) 7.62×51mm NATO full metal jacket boat-tail round specifically designed for Match purposes. The round was introduced as the XM118 match in 1963 and was produced at both Frankford Arsenal and Lake City Army Ammunition Plant. It was standardized as M118 match in mid-1965. It used the same bullet as the .30-06 Springfield M72 match ball round, match-grade brass cartridges, and used fitted No. 43 primers. Production ceased at Frankford in 1965 but continued at Lake City until the early 1980s. Lake City used dedicated equipment to produce the ammo up until the mid-1970s and during that time the quality of the ammunition was quite good. When they ceased using dedicated machinery the quality of the ammo had a very noticeable decline.[41]
• Cartridge, caliber 7.62mm, NATO, ball, special, M118 (United States): 173-grain (11.2 g) 7.62×51mm NATO full metal jacket boat-tail round specifically designed for match purposes. Produced by Lake City Army Ammunition Plant. This is an interim match round which utilized standard M80 ball brass cartridges with the 173-grain (11.2 g) full-metal jacketed ball boat-tailed (FMJBT) bullet and staked No. 34 or No. 36 primers. During this period in the early to late 1980s the performance of the round declined. Powder, primers, and brass were the same as standard ball rounds; bullets and powder charges varied in weight due to worn machinery and poor quality control. Since it could not be called "match" due to its erratic trajectory, it was renamed "special ball". Snipers used to test shoot batches of ammo, find a batch that shot well (or at least consistently), then zeroed their weapon to that batch and tried to procure as much of that ammo as possible.[41]

Linked belts of Lake City 7.62 mm M80 ball ammunition

• Cartridge, caliber 7.62mm, NATO, ball, special, M118LR (United States): 175-grain (11.3 g) 7.62×51mm NATO match-grade round specifically designed for long-range sniping. It uses a 175-grain (11.3 g) Sierra Match King hollow point boat-tail bullet. Produced at Lake City Army Ammunition Plant. The propellant's noticeable muzzle flash and temperature sensitivity led to the development of the MK 316 MOD 0 for special operations use.
• Cartridge, caliber 7.62mm, NATO, frangible, M160 (United States): 108.5-grain (7.0 g) 7.62×51mm NATO frangible bullet, upon striking a target, disintegrates, leaving a mark at the point of impact.
• Cartridge, caliber 7.62mm, NATO, dummy, M172 (United States): 7.62×51mm NATO cartridge is inert and is used to test the mechanism and metallic link belts of 7.62mm weapons. The cartridge is identified by a black oxide finish over the entire round and has no primer. There is no vent hole in the primer pocket.
• Cartridge, caliber 7.62mm, NATO, ball, overhead fire, XM178 (United States): 7.62×51mm NATO overhead fire application (OFA) cartridge using a solid turned gilding metal (GM) bullet. These were developed to make the OFA cartridges safer since there would be no small pieces of bullet that could separate and fall on the troops. Never adopted.
• Cartridge, caliber 7.62mm, NATO, tracer, overhead fire, XM179 (United States): 7.62×51mm NATO overhead fire application (OFA) cartridge using a solid, turned GM bullet. These were developed to make the OFA cartridges safer since there would be no small pieces of bullet that could separate and fall on the troops. XM179/XM180 difference is the amount of trace mixture. Never adopted.
• Cartridge, caliber 7.62mm, NATO, tracer, overhead fire, XM180 (United States): 7.62×51mm NATO overhead fire application (OFA) cartridge using a solid, turned GM bullet. These were developed to make the OFA cartridges safer since there would be no small pieces of bullet that could separate and fall on the troops. XM179/XM180 difference is the amount of trace mixture. Never adopted.
• Cartridge, caliber 7.62mm, NATO, blank, XM192 (United States): 7.62×51mm short-case rose-crimped blank. Never adopted.
• Cartridge, caliber 7.62mm, NATO, duplex, M198 (green tip) (United States): 7.62×51mm NATO duplex ball round with two 84-grain (5.4 g) bullets. The developmental designation was T314E3. It was meant to increase the M14's volume of fire by doubling the number of bullets it could fire per minute. Green cartridge tip.
• Cartridge, caliber 7.62mm, NATO, ball, low recoil, XM256 (United States): 7.62×51mm NATO single 82-grain (5.3 g) bullet from M198 round. Another attempt to control the M14 in full auto mode or for small stature troops. White cartridge tip. Never adopted.
• Cartridge, caliber 7.62mm, NATO, tracer, M276 (United States): 7.62×51mm NATO so-called "dim tracer" with reduced effect primarily for use with night vision devices, violet bullet tip.
• Cartridge, caliber 7.62mm, NATO, match, M852 (United States): 168-grain (10.9 g) 7.62×51mm NATO hollow-point boat-tail cartridge, specifically designed for use in national match competitions. It was dubbed "Mexican match" because it was based on the international match loading used at the Pan-Am Games in Mexico. It used standard brass, primer, and propellant, but used a match-grade bullet. It was later approved by U.S. Army JAG in the 1990s for combat use by snipers. It replaced the M118SB as the standard match round. The bullet was very accurate at around 300 meters (competition match ranges) but suffered at longer ranges.
• Cartridge, caliber 7.62mm, NATO, saboted light armor penetrator, M948 (United States): 7.62×51mm NATO saboted light armor penetrator cartridge. Adopted in limited quantities only by U.S. Army.[42]
• Cartridge, caliber 7.62mm, NATO, saboted light armor penetrator tracer, M959 (United States): 7.62×51mm NATO saboted light armor penetrator cartridge with tracer element. Adopted in limited quantities only by U.S. Army.[42]
• Cartridge, caliber 7.62mm, NATO, ball, training, M973 (United States): 7.62×51mm NATO SRTA ball training round. Has air brake to reduce the range the bullet will fly[43]
• Cartridge, caliber 7.62mm, NATO, tracer, training, M974 (United States): 7.62×51mm NATO SRTA tracer training round. Has air brake to reduce the range the bullet will fly[43]
• Cartridge, caliber 7.62mm, NATO, armor piercing, M993 (United States): 126.6 grains (8.2 g) 7.62×51mm NATO armor-piercing round, black cartridge tip. Can penetrate 18 mm of RHA at 100 meters.[44]
• Cartridge, caliber 7.62mm special ball, long range, MK 316 MOD 0 (United States): A 175-grain (11.3 g) round specifically designed for long-range sniping consisting of Sierra MatchKing hollow-point boat-tail projectiles, Federal Cartridge Company match cartridge cases and Gold Medal match primers. The propellant has been verified as IMR 4064 (per NSN 1305-01-567-6944 and Federal Cartridge Company Contract/Order Number N0016408DJN28 and has a charge weight per the specs of 41.745-grain (2.7 g).[45]
• Cartridge, caliber 7.62mm, NATO, ball, barrier, T762TNB1 MK319 MOD 0 (United States): 7.62×51mm NATO enhance behind barrier performance enhance function and casualty and muzzle flash requirements in short barrel carbines, 130 grains (8.4 g).[45]