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The .338 Lapua Magnum (8.6×70 mm or 8.58×70 mm) is a rimless, bottlenecked, centerfire rifle cartridge. It was developed during the 1980s as a high-powered, long-range cartridge for military
sniper A sniper is a military/paramilitary marksman who engages targets from positions of concealment or at distances exceeding the target's detection capabilities. Snipers generally have specialized training and are equipped with high-precision r ...
s. It was used in the War in Afghanistan and the Iraq War. As a result of this, it has become widely available. The loaded .338 cartridge is in diameter (rim) and long. It can penetrate better-than-standard military
body armor Body armor, also known as body armour, personal armor or armour, or a suit or coat of armor, is protective clothing designed to absorb or deflect physical attacks. Historically used to protect military personnel, today it is also used by variou ...
at ranges of up to , and has a maximum effective range of about with C.I.P. conforming ammunition at sea level conditions. Muzzle velocity is dependent on barrel length, seating depth, and powder charge, and varies from for commercial loads with bullets, which corresponds to about of muzzle energy. British military issue overpressure .338 Lapua Magnum cartridges with overall length, loaded with LockBase B408 very-low-drag bullets fired at 936 m/s (3,071 ft/s) muzzle velocity fired from a L115A3 Long Range Rifle were used in November 2009 by British sniper Corporal of Horse (CoH) Craig Harrison to establish a new record for the longest confirmed sniper kill in combat, at a range of (since broken). In reports, CoH Harrison mentions the environmental conditions at Musa Qala were perfect for long-range shooting: no wind, mild weather, and clear visibility. In addition to its military role, it is increasingly used by
hunter Hunting is the human activity, human practice of seeking, pursuing, capturing, or killing wildlife or feral animals. The most common reasons for humans to hunt are to harvest food (i.e. meat) and useful animal products (fur/hide (skin), hide, ...
s and civilian long-range shooting enthusiasts. The .338 Lapua Magnum is capable of taking down any big game animal, though its suitability for some dangerous game (Cape buffalo, hippopotamus, white rhinoceros, and elephant) is arguable unless accompanied by a larger "backup" caliber: "There is a huge difference between calibers that will kill an elephant and those that can be relied upon to stop one." In Namibia, the .338 Lapua Magnum is legal for hunting Africa's big five game if the loads have at least muzzle energy.


History


Initial development

In 1983, Research Armament Industries (RAI) in the United States began development of a new, long-range sniper cartridge capable of firing a , diameter bullet at , that could lethally penetrate five layers of military body armor at . After preliminary experiments, a
.416 Rigby The .416 Rigby is a rifle cartridge designed in 1911 by London based gunmaker John Rigby & Company, for hunting dangerous game. It is the first cartridge to use a bullet of .416 inch (10.57 mm) diameter. The rifles, as built by John Rigby & Co ...
case necked down to take a
bullet A bullet is a kinetic projectile, a component of firearm ammunition that is shot from a gun barrel. Bullets are made of a variety of materials, such as copper, lead, steel, polymer, rubber and even wax. Bullets are made in various shapes and co ...
was selected, since this diameter presents an optimum of sectional density and penetrating capability for practical spin-stabilized rifle bullets (bullets up to about 5 to 5.5 calibers in length). The .416 Rigby is an English big game cartridge designed in 1911 to accommodate 325 MPa (47,137 psi) pressures. One of the disadvantages of these old cartridge cases, which were intended for firing cordite charges instead of modern smokeless powder, is the thickness of the sidewall just forward of the web. During ignition, the cartridge's base, just forward of the bolt face, is not supported. During the process, RAI employed Jim Bell and Brass Extrusion Labs Ltd. (B.E.L.L.) of Bensenville, Illinois, to make the ''.338/416'' or ''8.58×71 mm'' cartridge cases, Hornady produced bullets, and RAI built a sniper rifle under contract for the U.S. Navy. RAI found that the BELL cases did not fulfill the requirements, since they were modified low pressure .416 Rigby cases. Pressed by military deadlines, RAI looked for another case producer and contacted Lapua of Finland in 1984. RAI was forced to drop out of the program due to financial difficulties. Subsequently, Lapua of Finland put this cartridge into limited production.Barnes, Frank C., ''Cartridges of the World 8th Edition'', edited by M. L. McPherson, DBI Books, 1997, . The .338/416 rifle program was later canceled when the contractors were unable to make the cartridge meet the project's velocity target of for a bullet, due to excessive pressures rupturing cartridge cases.


Final development

The current .338 Lapua Magnum cartridge was developed as a joint venture between the Finnish rifle manufacturer SAKO and the British rifle manufacturer Accuracy International, along with the Finnish ammunition manufacturer Lapua, or more officially Nammo Lapua Oy, which since 1998 is part of the Nordic Ammunition Group (Nammo). Lapua opted to redesign the .338/416 cartridge. In the new case design, particular attention was directed toward thickening and metallurgically strengthening the case's web and sidewall immediately forward of the web. In modern solid head cases, the hardness of the brass is the major factor determining a case's pressure limit before undergoing plastic deformation. Lapua tackled this problem by creating a hardness distribution ranging from the head and web (hard) to the mouth (soft) as well as a strengthened (thicker) case web and sidewall immediately forward of the web. This resulted in a very pressure-resistant case, allowing it to operate at high pressure and come within 15 m/s (50 ft/s) of the original velocity goal. Lapua also designed a .338 caliber lock base B408 full metal jacket bullet, modeled after its .30 caliber lock base bullet configuration. The result was the .338 Lapua Magnum cartridge which was registered with C.I.P. (
Commission Internationale Permanente pour l'Epreuve des Armes à Feu Portatives Commission or commissioning may refer to: Business and contracting * Commission (remuneration), a form of payment to an agent for services rendered ** Commission (art), the purchase or the creation of a piece of art most often on behalf of another ...
) in 1989. With the procurement by the Dutch Army, the cartridge became NATO codified. The .338 Lapua Magnum fills the gap between weapons chambered for standard military rounds such as the
7.62×51mm NATO The 7.62×51mm NATO (official NATO nomenclature 7.62 NATO) is a rimless, bottlenecked rifle cartridge. It is a standard for small arms among NATO countries. First developed in the 1950s, the cartridge had first been introduced in U.S. service fo ...
and large, heavy rifles firing the .50 BMG cartridge. It also offers an acceptable amount of barrel wear, which is important to military snipers who tend to fire thousands of rounds a year in practice. This was achieved by coupling a sensible case volume (7.40 ml) to bore area (56.86 mm2/0.5686 cm2) ratio (13.01 Oratio) with ample space for loading relatively long slender projectiles that can provide good aerodynamic efficiency and external ballistic performance for the projectile diameter.The Finnish Army found out during a test/trials program and seven years of service that the barrels of their Sako
TRG-42 The Sako TRG is a bolt-action sniper rifle line designed and manufactured by Finnish firearms manufacturer SAKO of Riihimäki. The TRG-21 and TRG-22 are designed to fire standard .308 Winchester ( 7.62×51mm NATO) sized cartridges, while the TRG ...
sniper rifles lasted 7,000 to 8,000 rounds with Lapua lock base B408 factory ammunition before showing impermissible accuracy decay. The Finnish Army's consistent accuracy requirement for these rifles is less than one MOA at 1,000 m. If this requirement is not met the TRG-42 gets a new barrel. This is normal practice for active high-performance precision rifle operators who regard barrels as expendable items. The continuous use of very powerful handloads (which results in higher muzzle velocities) results in much quicker throat erosion reducing the TRG-42 barrel's accuracy life to 1,500 to 2,000 rounds.
Like every other comparable large magnum rifle cartridge, the .338 Lapua Magnum presents a stout recoil. An appropriate fitting
stock In finance, stock (also capital stock) consists of all the shares by which ownership of a corporation or company is divided.Longman Business English Dictionary: "stock - ''especially AmE'' one of the shares into which ownership of a company ...
and an effective muzzle brake helps to reduce recoil-induced problems, enabling the operator to fire more rounds before getting too uncomfortable to shoot accurately. Good factory loads, multiple projectile weights and factory special application ammunition are all available.In 1990, the US military Adjutant General's Office issued a legal opinion holding that the Sierra MatchKing bullet (and similar bullets of other manufacturers), despite being a hollow point design, is not designed specifically to cause greater damage or suffering in a human target, and in fact normally does not create a wound readily distinguishable from wounds caused by conventional full metal jacket bullets, and is therefore in their opinion legal under the Hague Convention for use in war. Due to its growing civilian popularity, several high-quality tactical and match (semi) custom
bolt actions Bolt-action is a type of manual firearm action that is operated by ''directly'' manipulating the bolt via a bolt handle, which is most commonly placed on the right-hand side of the weapon (as most users are right-handed). Most bolt-action ...
designed for the .338 Lapua Magnum are becoming available. These (semi) custom bolt-actions are used with other high-grade rifle and sighting components to build custom sporting and target rifles.


Users

The .338 Lapua Magnum cartridge is in law enforcement or military serviceworldrifles.com
.
use with: * : RENEASako TRG-42 * : Blaser Tactical 2 *:
Bangladesh Armed Forces The Bangladesh Armed Forces ( bn, বাংলাদেশ সশস্ত্র বাহিনী, Bangladesh Sashastra Bahinī) are the Armed forces, combined military forces of the Bangladesh, People's Republic of Bangladesh. It consists ...
- Accuracy International AWM * : Canadian ForcesC14 Timberwolf Medium Range Sniper Weapon System (MRSWS) *: Chilean ArmyAPR338 and
PGM 338 The PGM 338, also known as the PGM .338 LM (LM - Lapua Magnum) or PGM Mini-Hecate .338, is French sniper rifle from the early 1990's (being produced since 1993). It uses the .338 Lapua Magnum (8.6×70mm) cartridge, which remains supersonic up to a ...
Barrett Model 98B *: People's Liberation Army Ground ForceQBU-202 (military designation for the 8.6×70mm CS/LR35 rifle) *: TAP. * — Sako TRG-42 * : Military of DenmarkSako TRG-42 *: Military of Estonia reconnaissance units and special forces — Sako TRG-42. * : Finnish Defence ForcesSako TRG-42 * : French Army, GIGN and
Commandement des Opérations Spéciales The Commandement des Opérations Spéciales ( en, Special Operations Command) or COS is a joint staff charged with overseeing the various special forces of the French Army, Navy and Air and Space Force, bringing them all under a single operatio ...
PGM 338 The PGM 338, also known as the PGM .338 LM (LM - Lapua Magnum) or PGM Mini-Hecate .338, is French sniper rifle from the early 1990's (being produced since 1993). It uses the .338 Lapua Magnum (8.6×70mm) cartridge, which remains supersonic up to a ...
, Sako TRG-42, AWM .338 * : Police and military - Accuracy International AWM and Sako TRG series, as well as
Satevari MSWP The Satevari ( ka, სატევარი translated as "Dagger" ) MSWP is a proposed multi-caliber modular sniper rifle platform developed by STC Delta intended primarily for military but also limited civilian use. It was designed as conve ...
. Domestic analogue .338 GBM produced by STC Delta * : Bundeswehr
Haenel RS9 The Haenel RS9 is a bolt action sniper rifle manufactured by C.G. Haenel. It is the Bundeswehr's medium-range sniper rifle and replaces the Accuracy International AWM in the Kommando Spezialkräfte and Kommando Spezialkräfte Marine. History ...
designated as G29 in service with the special forces; replacing the G22, Erma SR-100, AMP Technical Services DSR-1, GOL Sniper Magnum * : Anti-Terrorist Unit EKAMSako TRG-41 * : Hungarian Police Security Service (Rendészeti Biztonsági Szolgálat) - Unique-Alpine TPG-1 (Taktische Prazisions Gewehr-1) * : KopassusAccuracy International AWM .338 * : Irish ArmyAccuracy International AWM .338 * : Infantry - H-S Precision Pro Series 2000 HTR Special forces —
McMillan Tac-338 MacMillan, Macmillan, McMillen or McMillan may refer to: People * McMillan (surname) * Clan MacMillan, a Highland Scottish clan * Harold Macmillan, British statesman and politician * James MacMillan, Scottish composer * William Duncan MacMillan ...
and
PGM 338 The PGM 338, also known as the PGM .338 LM (LM - Lapua Magnum) or PGM Mini-Hecate .338, is French sniper rifle from the early 1990's (being produced since 1993). It uses the .338 Lapua Magnum (8.6×70mm) cartridge, which remains supersonic up to a ...
, YAMAMBarrett MRAD * : Sako TRG-42 * : Lithuanian Armed Forces
Accuracy International AXMC The Accuracy International Arctic Warfare rifle is a bolt-action sniper rifle designed and manufactured by the British company Accuracy International. It has proved popular as a civilian, police, and military rifle since its introduction in ...
* : '' Pasukan Gerakan Khas'' — Accuracy International AWMAccuracy International AX338 * :
Dutch military The Netherlands Armed Forces ( nl, Nederlandse krijgsmacht) are the military, military services of the Kingdom of the Netherlands. The core of the armed forces consists of the four service branches: the Royal Netherlands Navy (), the Royal Nethe ...
Accuracy International AWM and AXMC, Sako TRG-41 * : New Zealand Defence ForceBarrett MRAD * : GROMAccuracy International AWM, 1 Pułk Specjalny Komandosów * — Accuracy International AWM
Accuracy International AXMC The Accuracy International Arctic Warfare rifle is a bolt-action sniper rifle designed and manufactured by the British company Accuracy International. It has proved popular as a civilian, police, and military rifle since its introduction in ...
* :
Alpha Group Spetsgruppa "A", also known as Alpha Group (a popular English name), or Alfa, whose official name is Directorate "A" of the FSB Special Purpose Center (TsSN FSB) (Russian: Спецназ ФСБ "Альфа"), is an elite stand-alone sub-unit o ...
and
SOBR The Special Rapid Response Unit or SOBR (russian: СОБР - Специальный Отряд Быстрого Реагирования, Spetsial'niy Otryad Bystrovo Reagirovaniya, lit. ''Special Unit of Quick Response''), from 2002 to 2011 k ...
Accuracy International AWM * :
Special Brigade Special or specials may refer to: Policing * Specials, Ulster Special Constabulary, the Northern Ireland police force * Specials, Special Constable, an auxiliary, volunteer, or temporary; police worker or police officer Literature * ''Specia ...
Sako TRG-42. * :
PGM 338 The PGM 338, also known as the PGM .338 LM (LM - Lapua Magnum) or PGM Mini-Hecate .338, is French sniper rifle from the early 1990's (being produced since 1993). It uses the .338 Lapua Magnum (8.6×70mm) cartridge, which remains supersonic up to a ...
* : Military of Slovenia
PGM 338 The PGM 338, also known as the PGM .338 LM (LM - Lapua Magnum) or PGM Mini-Hecate .338, is French sniper rifle from the early 1990's (being produced since 1993). It uses the .338 Lapua Magnum (8.6×70mm) cartridge, which remains supersonic up to a ...
* : GOESako TRG-41 * : Sako TRG-42 *: Sako TRG-42 * : Used by the army snipers: the Netherlands donated Accuracy International AWM rifles to Ukraine in 2022. * :
British military The British Armed Forces, also known as His Majesty's Armed Forces, are the military forces responsible for the defence of the United Kingdom, its Overseas Territories and the Crown Dependencies. They also promote the UK's wider interests, su ...
Accuracy International AWM .338L115A3 Long Range Rifle
British Army.
* : US Navy Special Warfare
McMillan Tac-338 MacMillan, Macmillan, McMillen or McMillan may refer to: People * McMillan (surname) * Clan MacMillan, a Highland Scottish clan * Harold Macmillan, British statesman and politician * James MacMillan, Scottish composer * William Duncan MacMillan ...
The .338 Lapua Magnum has been designated a "cartridge of interest" by the National Defense Industrial Association (NDIA). It is being groomed to replace the
.300 Winchester Magnum The .300 Winchester Magnum (also known as .300 Win Mag or .300 WM) (7.62×67mmB, 7.62x66BR) is a belted, bottlenecked magnum rifle cartridge that was introduced by the Winchester Repeating Arms Company in 1963. The .300 Winchester Magnum is a m ...
and the .50 BMG for anti-personnel long-range service in the U.S. military. On June 17, 2008, the U.S. government issued a market survey to support a requirement for a precision sniper rifle (PRS) to possibly replace the currently-fielded bolt-action SOF Sniper Syst's0126. On 7 March 2013, the
Remington MSR The Modular Sniper Rifle, or MSR, is a bolt-action sniper rifle developed and produced by Remington Arms for the United States Army. It was introduced in 2009, and was designed to meet specific United States Army and USSOCOM Precision Sniper Ri ...
was declared the winner of the precision sniper rifle competition. Remington announced that the MSR had won on 8 March, and it was publicly confirmed on 9 March. This was followed by a $79.7 million contract for 5,150 rifles with suppressors, along with 4,696,800 rounds of ammunition to be supplied over the next ten years. The contract was awarded on 12 September 2013. Remington Defense would produce the Mk 21 sniper rifles and utilized two other companies for other system components, with
Barnes Bullets Barnes may refer to: People *Barnes (name), a family name and a given name (includes lists of people with that name) Places United Kingdom * Barnes, London, England ** Barnes railway station **Barnes Bridge railway station **Barnes Railway Brid ...
for ammunition and Advanced Armament Corporation for muzzle brakes and suppressors; all three companies are subsidiaries of Remington Outdoor Company. However, it was then decided that the Mk 21 did not conform to SOCOM requirements, and the program was re-competed with the Barrett MRAD selected in 2019 as the Mk 22 Advanced Sniper Rifle solution. The US military opted to use
7.62×51mm NATO The 7.62×51mm NATO (official NATO nomenclature 7.62 NATO) is a rimless, bottlenecked rifle cartridge. It is a standard for small arms among NATO countries. First developed in the 1950s, the cartridge had first been introduced in U.S. service fo ...
,
.300 Norma Magnum The .300 Norma Magnum, also known as .300 NM or "300 Norma" for short, is a centerfire magnum rifle cartridge developed by Swedish ammunition manufacturer Norma Precision. The .300 Norma Magnum uses a .338 Norma Magnum case necked down to the ...
and instead of the .338 Lapua Magnum the .338 Norma Magnum chambering in their Mk 22 rifles, which have a field-convertible barrel/chambering switch capability.


Cartridge dimensions

Extremely thick-walled brass results in a 7.40 ml (114 grains H2O) cartridge case capacity for the .338 Lapua Magnum. The exterior shape of the case was designed to promote reliable feeding and extraction in bolt action, semi-automatic, and
automatic firearm An automatic firearm is an auto-loading firearm that continuously chambers and fires rounds when the trigger mechanism is actuated. The action of an automatic firearm is capable of harvesting the excess energy released from a previous discharg ...
s alike, under extreme conditions. .338 Lapua Magnum maximum C.I.P. cartridge dimensions. All sizes in millimeters (mm). Americans define the shoulder angle at alpha/2 ≈ 20 degrees. The common
rifling In firearms, rifling is machining helical grooves into the internal (bore) surface of a gun's barrel for the purpose of exerting torque and thus imparting a spin to a projectile around its longitudinal axis during shooting to stabilize the pro ...
twist rate for this cartridge is 254 mm (1 in 10 in), 6 grooves, Ø lands = 8.38 mm, Ø grooves = 8.58 mm, land width = 2.79 mm and the primer type is large rifle magnum. According to the official C.I.P. (Commission Internationale Permanente pour l'Epreuve des Armes à Feu Portatives) decisions and tables edition 2007 the .338 Lapua Magnum case can handle up to Pmax piezo pressure. This now prevails over the C.I.P. decisions and tables edition 2003, that rated the .338 Lapua Magnum at Pmax maximum piezo pressure. The Pmax maximum piezo pressure C.I.P. ruling for the
.300 Lapua Magnum The .300 Lapua Magnum (7.62×70mm) is a specialized rimless bottlenecked centerfire cartridge developed for long-range rifles. The commercially successful .338 Lapua Magnum cartridge has functioned as the parent case for the .300 Lapua Magnum, ...
cartridge, which is based on the same case, was at the time not accordingly changed. In C.I.P. regulated countries every rifle cartridge combo has to be proofed at 125% of the prevailing maximum C.I.P. pressure to certify for sale to consumers. This means that .338 Lapua Magnum chambered arms in C.I.P. regulated countries are currently (2013) proof tested at PE piezo pressure. Lapua has been ambivalent on the maximum piezo pressure of this cartridge. In the article "From an American dream to a Finnish success story" by Janne Pohjoispää, Lapua propagates the C.I.P. 2007 ruling of maximum piezo pressure. To further complicate matters the mentioned 56,000
CUP A cup is an open-top used to hold hot or cold liquids for pouring or drinking; while mainly used for drinking, it also can be used to store solids for pouring (e.g., sugar, flour, grains, salt). Cups may be made of glass, metal, china, c ...
C.I.P. copper crusher pressure translates to around C.I.P. piezo pressure according to a study on the conversion from CUP to PSI for rifle cartridges by Denton Bramwell. The C.I.P. 2003 ruling of piezo pressure is corroborated by Lapua Australia in the "History and development of the .338 Lapua Magnum" article by Alan C. Paulson. A reverse engineering simulation with
QuickLOAD QuickLOAD is an internal ballistics predictor computer program for firearms. For computations apart from other parameters, * the cartridge * the projectile (bullet) * the gun barrel length * the cartridge overall length * the propellant type and ...
internal ballistic software predicted that Lapua load their factory .338 Lapua Magnum ammunition at about piezo pressure, as Paulson asserts in his article. The large bolt face combined with the maximum pressure means that the .338 Lapua Magnum is normally only chambered in rifles that are capable of handling such large high-pressure cartridges, and thus high bolt thrust, safely. Chambering such powerful super magnum cartridges in rifles intended for normal magnum rifle cartridges and using high-pressure loads can cause serious or fatal injury to the shooter and bystanders. The American
.338-378 Weatherby Magnum The .338-378 Weatherby Magnum started out as the wildcat cartridge, .338-378 Keith-Thomson Magnum during the early 1960s. Keith and Thomson are Elmer Keith and R.W. "Bob" Thomson. The 338-378 Keith-Thomson Magnum is a quarter of an inch short ...
cartridge introduced in 1998 and the American
.338 Remington Ultra Magnum The .338 Remington Ultra Magnum is a .338 caliber rifle cartridge introduced by Remington Arms in 2002. Design It is a beltless, rebated rim cartridge based on the .300 Remington Ultra Magnum case shortened .090" and necked-up to accept a 0.338 ...
(.338 RUM) cartridge introduced in 2000 are probably the closest ballistics-wise to the .338 Lapua Magnum commercially available . The .338-378 Weatherby Magnum is, however, a belted cartridge and the .338 Remington Ultra Magnum is a
rebated rim A rim is an external flange that is machined, cast, molded, stamped, or pressed around the bottom of a firearms cartridge. Thus, rimmed cartridges are sometimes called "flanged" cartridges. Almost all cartridges feature an extractor or headspacing ...
cartridge. The American
SAAMI The Sporting Arms and Ammunition Manufacturers' Institute (SAAMI, pronounced "Sammy") is an association of American manufacturers of firearms, ammunition, and components. SAAMI is an accredited standards developer that publishes several Americ ...
(Sporting Arms and Ammunition Manufacturers' Institute) has no normal voluntary guidelines for the .338 Lapua Magnum. On 14 January 2013 it opted to use the metric C.I.P. rulings and add some dimensions that have no C.I.P. analog.


Supersonic range performance of the .338 Lapua Magnum


Performance with C.I.P. conforming cartridges

For a typical .338 Lapua Magnum high-end factory military sniper rifle like the Sako
TRG-42 The Sako TRG is a bolt-action sniper rifle line designed and manufactured by Finnish firearms manufacturer SAKO of Riihimäki. The TRG-21 and TRG-22 are designed to fire standard .308 Winchester ( 7.62×51mm NATO) sized cartridges, while the TRG ...
with a long 305 mm (1 in 12 inch) rifling twist rate barrel at sea level, is considered to be the maximum shooting distance for man-sized targets. When using standard Lapua military 16.2 g (250 gr) loads it has a supersonic range of under warm summer conditions at a muzzle velocity of . However, to be able to maintain 80 to 90% hit probability on non-moving reactive army targets, this maximum shooting distance has to be reduced to at freezing point conditions or in Arctic winter conditions, when the muzzle velocity may drop to —i.e. only during optimal warm summer conditions the maximum shooting distance is realistically achievable. Loaded with more aerodynamic very-low-drag bullets such as the traditionally lead-cored 19.44 g (300 gr) Lapua Scenar GB528 VLD bullet ( G1 BC = 0.736) or the Lost River Ballistics J40 .338 17.5 gram (270 gr) CNC manufactured mono-metal bullet (G1 BC = 0.871) the long-range performance and supersonic range of .338 Lapua Magnum rifles can be improved. These longer very-low-drag bullets require a 254 mm (1 in 10 inch) twist rate to stabilize them. Due to the lower practically possible muzzle velocities for a relative heavy bullet like the 19.44 g (300 gr) Lapua Scenar GB528 VLD bullet it gains about extra supersonic range under International Standard Atmosphere sea level conditions (
air density The density of air or atmospheric density, denoted '' ρ'', is the mass per unit volume of Earth's atmosphere. Air density, like air pressure, decreases with increasing altitude. It also changes with variation in atmospheric pressure, temperature a ...
ρ = 1.225 kg/m3) at a muzzle velocity of 837 m/s (2750 ft/s) when compared to the standard 16.2 g (250 gr) Lapua Scenar GB488 VLD at a muzzle velocity of 915 m/s (3002 ft/s). For significant supersonic range improvement, the aerodynamic efficiency of the employed bullets has to be significantly improved without sacrificing a lot of practically achievable muzzle velocity - meaning that besides the coefficient of drag of the projectile weight is also an important parameter for its actual downrange flight behavior. The .338 17.5 gram (270 gr) Lost River Ballistic Technologies J40 match bullet made out of a copper-nickel alloy is one of the most aerodynamic .338 calibre bullets available. It has an supersonic range under optimal warm summer conditions at a muzzle velocity of . This makes engaging static targets up to feasible.


Performance improvement experiments with non-C.I.P.-conforming cartridges

Improvement beyond this standard while still using standard .338 Lapua Magnum brass is possible, but the bullets have to be very long (over 5.5 calibers in length) and the normal cartridge overall length of 93.5 mm has to be exceeded, making such cartridges wildcats. The common 254 mm (1:10 inch) rifling twist rate also has to be tightened to stabilize very long projectiles. Such commercially non-existent cartridges are termed "wildcats". The use of a wildcat .338 Lapua Magnum-based cartridge demands the use of a custom or customized rifle with an appropriately cut chamber and fast-twist bore. The firearm action and if a repeating arm is required the magazines must also be able to cope with dimensional increases. An example of such a special .338 caliber extreme range bullet is the German CNC manufactured mono-metal 18.92 gram (292 gr) LM-105 (Cd = 0.2487 at
Mach Mach may refer to Mach number, the speed of sound in local conditions. It may also refer to: Computing * Mach (kernel), an operating systems kernel technology * ATI Mach, a 2D GPU chip by ATI * GNU Mach, the microkernel upon which GNU Hurd is bas ...
2.216 – this drag coefficient and the corresponding G1, G7 and G8 ballistic coefficients are established by Doppler radar
measurements Measurement is the quantification of attributes of an object or event, which can be used to compare with other objects or events. In other words, measurement is a process of determining how large or small a physical quantity is as compared t ...
). The LM-105 has a supersonic range of ≈ at a muzzle velocity of under International Standard Atmosphere sea level conditions (
air density The density of air or atmospheric density, denoted '' ρ'', is the mass per unit volume of Earth's atmosphere. Air density, like air pressure, decreases with increasing altitude. It also changes with variation in atmospheric pressure, temperature a ...
ρ = 1.225 kg/m3). The 2010 version of the LM-105 bullet has an overall length of or 6.33 calibers and derives its exceptionally low drag from a radical LD Haack or Sears-Haack profile in the bullet's nose area. Rifles chambered for this wildcat cartridge, with a cartridge overall length of , and equipped with custom made 178 mm (1:7 inch) progressive twist rate long barrels with a 2° cone-angle (the standard C.I.P. cone-angle for the .338 Lapua Magnum is 6°) cone area finished first and second at several long-range competitions. Its most recent win (2007) was in an international
special forces Special forces and special operations forces (SOF) are military units trained to conduct special operations. NATO has defined special operations as "military activities conducted by specially designated, organized, selected, trained and equip ...
and police sniper competition in Switzerland against rifles chambered for
7.62×51mm NATO The 7.62×51mm NATO (official NATO nomenclature 7.62 NATO) is a rimless, bottlenecked rifle cartridge. It is a standard for small arms among NATO countries. First developed in the 1950s, the cartridge had first been introduced in U.S. service fo ...
up to .50 BMG at ranges from 100 m – 1,500 m (109 yd – 1,640 yds). The LM-105 bullet exhibited its very low wind drift susceptibility notably at ranges beyond . A real-world average G1 BC of around 0.83 or a G7 BC of about 0.42 is commonly adopted by the users of this bullet, for making long-range trajectory predictions using ballistics calculators. In contrast the LM-105 designer Lutz Möller originally calculated an optimistic G1 BC of ≈ 0.93 and a supersonic range of ≈ at a muzzle velocity of under International Standard Atmosphere sea level conditions (
air density The density of air or atmospheric density, denoted '' ρ'', is the mass per unit volume of Earth's atmosphere. Air density, like air pressure, decreases with increasing altitude. It also changes with variation in atmospheric pressure, temperature a ...
ρ = 1.225 kg/m3). The .343 Lapua Magnum LM-107 was a wildcat cartridge under development based on the standard .338 Lapua Magnum cartridge case. The LM-107 was hoped to boost the ballistic performance of the LM-105 by achieving an increase in supersonic range. The 19.3 g (298 gr) LM-107 projectile design is long and has a Haack profiled nose and an Adams profiled tail. The rifling twist rate for the .343 Lapua Magnum LM-107 wildcat cartridge was chosen at 180 mm (1:7 inch), Ø lands = 8.72 mm, Ø grooves = 8.45 mm and loaded with the LM-107 projectile has a cartridge overall length of . The length of the neck is increased from 8,31 to 8,50 mm to support the bigger LM-107 bullet. Several other dimensions of the .338 Lapua Magnum parental cartridge are also changed. The shoulder angle gets steepened from 40° to 60° and the body taper is set at 1°. The throat area is set at a 2° cone-angle. All these modifications make the .343 Lapua Magnum a fairly comprehensively revised wildcat cartridge. Out of a long progressive twist barrel Möller expected to achieve muzzle velocity. If Möller's design assumptions are correct the LM-107 projectile with a calculated G1 BC of 1.02 will offer a supersonic range of ≈ at a muzzle velocity of under International Standard Atmosphere sea level conditions (air density ρ = 1.225 kg/m3).


As a parent case


.300 Lapua Magnum

The commercially successful .338 Lapua Magnum cartridge has functioned as the parent case for the
.300 Lapua Magnum The .300 Lapua Magnum (7.62×70mm) is a specialized rimless bottlenecked centerfire cartridge developed for long-range rifles. The commercially successful .338 Lapua Magnum cartridge has functioned as the parent case for the .300 Lapua Magnum, ...
, which is essentially a necked-down version of the .338 Lapua Magnum. The .338 cartridge case was used for this since it has the capability to operate with high chamber pressures which, combined with smaller and hence lighter bullets, result in very high muzzle velocities. The Finnish ammunition manufacturer Lapua got the .300 Lapua Magnum C.I.P. certified, so it became an officially registered and sanctioned member of the Finnish "family" of super magnum rifle cartridges. The .300 Lapua Magnum is not commercially available and currently exists only as a C.I.P. datasheet. It is however still used by a few shooters who produce the cases from .338 Lapua Magnum brass by reshaping the shoulder and neck, and handloading it with .30 calibre bullets. The .300 Lapua Magnum has a 7.33 ml (113 grains H2O) cartridge case capacity. .300 Lapua Magnum maximum C.I.P. cartridge dimensions. All sizes in millimeters (mm). Americans define the shoulder angle at alpha/2 ≈ 25 degrees. The common rifling twist rate for this cartridge is 240 mm (1 in 9.45 in), 4 grooves, Ø lands = 7.62 mm, Ø grooves = 7.82 mm, land width = 4.47 mm and the primer type is large rifle magnum. According to the official C.I.P. rulings the .300 Lapua Magnum can handle up to Pmax piezo pressure. This now prevails over the C.I.P. decisions and tables edition 2007, that rated the .300 Lapua Magnum at Pmax piezo pressure. In C.I.P. regulated countries every rifle cartridge combo has to be proofed at 125% of this maximum C.I.P. pressure to certify for sale to consumers. This means that .300 Lapua Magnum chambered arms in C.I.P. regulated countries are currently (2013) proof tested at PE piezo pressure. The large diameter bolt face, combined with the high maximum pressure, means that the .300 Lapua Magnum is normally only chambered in rifles that are capable of handling the resulting high bolt thrust, safely. Chambering such powerful super magnum cartridges in rifles intended for normal magnum rifle cartridges and using loads can cause serious or fatal injury to the shooter and bystanders.


7.62 UKM

The .338 Lapua Magnum cartridge is also used as the parent case for the German-designed
7.62 UKM The 7.62mm UKM .62×57mmis a specialized rimless bottlenecked centerfire cartridge developed for long-range rifles. The commercially successful .338 Lapua Magnum cartridge has functioned as the parent case for the 7.62mm UKM, which is essential ...
, which is essentially a necked-down shortened version of the .338 Lapua Magnum. The use of the .338 cartridge case with its capability to operate at high chamber pressures resulted in a magnum case capable of producing high muzzle velocities. The 7.62 UKM was developed by Michael Uekötter and was C.I.P.-certified in 2002, making it an officially registered and sanctioned member of the Finnish "family" of super magnum rifle cartridges. The 7.62 UKM is not commercially available and currently exists only as a C.I.P. datasheet. It is however still used by a few shooters who produce the cases from .338 Lapua Magnum brass by reshaping the shoulder and neck, and handloading it with .30 caliber bullets. The 7.62 UKM has a 5.84 ml (90 grains H2O) cartridge case capacity. 7.62 UKM maximum C.I.P. cartridge dimensions. All sizes in millimeters (mm). Americans define the shoulder angle at alpha/2 ≈ 20 degrees. The common rifling twist rate for this cartridge is 254 mm (1 in 10 in), 6 grooves, Ø lands = 7.62 mm, Ø grooves = 7.82 mm, land width = 2.79 mm and the primer type is large rifle magnum. According to the official C.I.P. rulings the 7.62 UKM Magnum can handle up to Pmax piezo pressure. This now prevails over the C.I.P. decisions and tables edition 2007, that rated the 7.62 UKM at Pmax piezo pressure. In C.I.P. regulated countries every rifle cartridge combo has to be proofed at 125% of this maximum C.I.P. pressure to certify for sale to consumers. This means that 7.62 UKM chambered arms in C.I.P. regulated countries are currently (2013) proof tested at PE piezo pressure.


.375 Swiss P

The .375 Swiss P (9.5×7 0mm) is a C.I.P. registered chambering introduced in 2021 and advertised by RUAG Ammotec as a cartridge that "fills the gap in ballistic performance between the .338 Lapua Magnum (8.6×70 mm) and the .50 BMG (12.7×99mm NATO)". As such, .375 Swiss P was designed to be relatively easily rechambered by a rebarreling as a performance upgrade in sturdily-built rifles originally designed around the .338 Lapua Magnum chambering. The .375 Swiss P is a rebated rim bottlenecked cartridge that shares its bolt face, rim diameter, overall length, and maximum operating pressure with the .338 Lapua Magnum chambering. It features a larger base diameter as found in the
.500 Jeffery The .500 Jeffery is a big-game rifle cartridge that first appeared around 1920, and was originally introduced by the August Schuler Company, a German firm, under the European designation "12.7×70mm Schuler" or ".500 Schuler". When offered by th ...
. This results in a (P1 - R1 = ) rebated rim.


Wildcats

The .338 Lapua Magnum case is also used as the parent case for a host of modified variants that are not officially registered with or sanctioned by C.I.P. or its American equivalent,
SAAMI The Sporting Arms and Ammunition Manufacturers' Institute (SAAMI, pronounced "Sammy") is an association of American manufacturers of firearms, ammunition, and components. SAAMI is an accredited standards developer that publishes several Americ ...
. By changing the shape of standard factory cases (decreasing case taper or changing the shoulder geometry) the wildcatter generally increases the case capacity of the factory parent cartridge case, allowing more propellant to be used to generate higher velocities. Besides changing the shape and internal volume of the parent cartridge case, wildcatters also can change the original caliber. Because the .338 Lapua offers a large and exceptionally sturdy, pressure-resistant cartridge case that can be relatively easily reloaded and hence be reused several times, it has become quite popular amongst wildcatters. With the .338 Lapua Magnum as the parent case wildcatters have created 7 mm (7 mm Allen Magnum, 7 mm Katzmeier, 7 mm Fatso), .30 (.30-338 Lapua (Triebel), .30 Wolf, 300 Allen Express), 8 mm (8 mm-338 Lapua (Triebel), LM-101), .338 (.338 Yogi, LM-105), .343 (.343 Lapua Magnum LM-107), 9.3 mm (9,3-338 Lapua Magnum (Triebel)), .375 (9.5×70 ELR) and .50 calibre (
.510 Whisper The .510 Whisper is a subsonic rifle cartridge developed by SSK Industries for use in suppressed rifles. It is capable of firing a .51-caliber bullet weighing at roughly . Overview The .510 Whisper (13×47 mm) is the second of two 1/2 inch ca ...
) variants. Tom Sarver used a .300 Hulk wildcat cartridge, which is basically a necked-down, blown out, shortened .338 Lapua Magnum variant, to achieve a diameter benchrest five-shot group on 7 July 2007, establishing a world record.Sarver Shoots 1.403″ Group at 1000 Yards
.


See also

*
12.7×55mm STs-130 The 12.7×55mm cartridge is used in some Russian firearms such as VKS bullpup sniper rifle and ShAK-12 bullpup battle rifle and RSh-12 revolver. The cartridge can carry a projectile weighing between from 108 grains and 1173 grains and is predo ...
*
6.5×47mm Lapua The 6.5×47mm Lapua (designated as the 6,5 × 47 Lapua by the C.I.P.) is a smokeless powder rimless bottlenecked rifle cartridge that was developed specifically for competition shooting by ammunition maker Nammo Lapua and the Swiss rifle manu ...
*
7.62 UKM The 7.62mm UKM .62×57mmis a specialized rimless bottlenecked centerfire cartridge developed for long-range rifles. The commercially successful .338 Lapua Magnum cartridge has functioned as the parent case for the 7.62mm UKM, which is essential ...
* 8 mm caliber * List of firearms * List of rifle cartridges * Table of handgun and rifle cartridges * List of sniper rifles


Notes


References


External links


Lapua product brochure .338 Lapua Magnum ammunition
(.338 Lapua Magnum and
.408 Chey Tac The .408 Cheyenne Tactical (designated 408 Chey Tac (10.36×77mm) by the C.I.P. from 2013 to 2021) is a specialized rimless, bottlenecked, centerfire cartridge for military long-range sniper rifles that was developed by Dr. John D. Taylor and m ...
chamberings)
.338 Lapua Magnum reloading data at Reloader's Nest




* ttps://web.archive.org/web/20111010060255/http://www.98bravo.com/lapua-338-magnum-exclusive-caliber-for-the-new-age-of-sniping.html Lapua 338 Magnum, Exclusive Caliber for The New Age of Sniping
.338 Lapua Magnum - "Generation II" ordnance development program by Caina Longbranch


* ttps://bobp.cip-bobp.org/uploads/tdcc/tab-i/338-lapua-mag-en.pdf C.I.P. TDCC sheet 338 Lapua Mag. {{DEFAULTSORT:338 Lapua Magnum British firearm cartridges Magnum rifle cartridges Military cartridges Pistol and rifle cartridges Nammo Lapua cartridges Military equipment introduced in the 1980s