8x68mm S
Encyclopedia
The 8x68mm S rimless
bottlenecked rifle
cartridge
(the S means it is intended for 8.2 mm (.323 in) groove diameter bullets) and its necked down sister cartridge
the 6.5x68mm
(no S, or anything else, required) were developed in the 1930s by Mr. Schüler of the August Schüler Waffenfabrik, Suhl, Germany as magnum hunting cartridges that would just fit and function in standard sized Mauser 98 bolt action rifles. This is one of the early examples where a de novo rifle cartridge
(the 8x68mm S and 6.5x68mm have no other cartridge as parent case) was developed by a gunsmith
to fit a specific popular and widespread type of rifle.
manufacturer RWS (Rheinisch-Westfälischen Sprengstoff factories) introduced both cartridges commercially in the spring of 1939. With the official certification of the .375 Hölderlin this German 68 mm "family" of magnum rifle cartridges that all share the same basic cartridge case got expanded 68 years later.
The cartridges in this German 68 mm cartridge "family" are, in the order of development:
The M 98 bolt actions of standard military Mauser 98 rifles have to be adapted by a competent gunsmith
to function properly with these magnum cartridges since they are longer and the cases have a larger diameter than the 8x57mm service cartridges. In properly adapted standard military Gewehr 98
or Karabiner 98k
service rifles the large 8x68mm S cartridges are however praised for very smooth and reliable feeding.
The widespread availability of standard size Mauser 98 rifles and the fact that the .375 H&H Magnum
cartridge and its necked down version the .300 H&H Magnum
with approximately 72.4 mm case length were too long to fit in standard sized Mauser 98 bolt action rifles makes the shorter 8x68mm S, 6.5x68mm and .375 Hölderlin interesting chambering options.
World War II
spoiled the commercial introduction and spread of the 8x68mm S amongst German hunters. The cartridge became due to its high performance and flat trajectory
popular after World War II when German hunters were allowed again to own and hunt with full bore rifles. The 8x68mm S performance also made that hunters who had problems with handling magnum cartridge recoil stepped down to less powerful but for German conditions adequate medium cartridges like the 8x57mm IS, 7x64mm
(Brenneke) or .30-06 Springfield
(also known as the 7.62x63mm in metric countries). Recoil sensitive shooters can fit an efficient muzzle brake
to significantly reduce the amount of recoil. With the help of a muzzle brake the 8x68mm S recoil is reduced to tolerable levels.
(86 grains
) H2O cartridge case capacity for the 8x68mm S. A rare feature of this German rimless bottlenecked centerfire cartridge design is that it has a slightly rebated rim
(P1 - R1 = 0.3 mm). A sign of the era in which the 8x68mm S was developed are the gently sloped shoulders. The exterior shape of the case was designed to promote reliable case feeding and extraction in bolt action rifles, under extreme conditions.
8x68mm S maximum C.I.P. cartridge dimensions. All sizes in millimetres (mm).
Americans would define the shoulder angle at alpha/2 ≈ 14.53 degrees. The common rifling
twist rate for this cartridge is 280 mm (1 in 11.02 in), 4 grooves, Ø lands = 7.89 mm, Ø grooves = 8.20 mm, land width = 4.40 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
) guidelines the 8x68mm S case can handle up to 440 MPa (63817 psi) 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.
The American .325 WSM
cartridge introduced in 2005 is probably the closest ballistic twin of the 8x68mm S. The .325 WSM is considerably shorter and fatter and has a more radical rebated rim (P1 -R 1 = 0.51 mm), much steeper shoulder angle (70 degrees / 35 degrees for Americans) and a shorter neck (7.82 mm). This makes the 8x68mm S case with its 9.11 mm long neck better suited for loading long heavier bullets and due to its sleeker exterior shape bound to cycle more reliably in bolt action rifles in extreme situations.
hunters often use 8x68mm S rifles in Africa for hunting plains game
, where American hunters would choose one of the .30 or .338 magnum cartridges. The 8x68mm S as a pure civil cartridge can be used in countries which ban civil use of former or current military ammunition.
Since there are not many factory loads available RWS currently (2007) offers 5 factory loads) and due to its good field reputation and efficiency, the 8x68mm S is often used by reload
ers. They have used this cartridge extensively to create powerful loads by handloading
. Whilst staying within the 440 MPa C.I.P. limit a 8x68mm S rifle with a 650 mm (25.59 in) long barrel and appropriate modern gun propellants (Vihtavuori N560) can be handloaded to propel a 12.96 gram (200 gr) 8 mm bullet like the Sierra MatchKing to a muzzle velocity of 927 m/s (3042 ft/s).
The 8x68mm S has a good long range accuracy reputation i.e. it is not hard to develop or find loads that will shoot 1 MoA or better out of decent standard mass produced rifles. Factory 8x68mm S rifles often have a 650 mm or 26 in barrel with a 280 mm (1 in 11 in) twist rate, which works well in daily life. This twist rate was chosen since the bullet jackets used in the 1930s were not strong enough to cope with the forces generated by the magnum muzzle velocities of the 8x68mm S. The 240 mm (1 in 9.45 in) twist rate normally found in the 8x57mm IS makes the 8x68mm S combined with modern bullets with jackets designed for magnum cartridges an excellent long range cartridge.
Reloaders use the 8x68mm S as a utility cartridge on all European game from fox
, roe deer
and chamois
upwards to the big European game like red deer
, moose
and brown bear
. These people realized that bullets with different characteristics can be utilized to produce varying effects on game. They also realized that from 8 mm caliber upwards the rise of sectional density and penetrating capability of practical spin stabilized rifle bullets (bullets up to 5 to 5.5 calibers in length) tends to flatten out.
This means that loaded with light, short and soft nosed 8 mm bullets the 8x68mm S can be used on remarkably small game. Loaded with heavy, long and hard (solid copper alloy) bullets the 8x68mm S offers enough speed derived power to penetrate heavy and dangerous game. The 8x68mm S is suitable for hunting almost any game animal on the planet, though certain sub-Saharan Africa
countries have a 9.53 mm (.375 in) minimum caliber rule for hunting Big Five game
- i.e. leopard
, lion
, cape buffalo, rhinoceros
and elephant
. In the Central African Republic
, where there are no ammunition
limits for hunting Big Five game
, the 8x68mm S is used successfully for hunting elephant
.
(Sporting Arms and Ammunition Manufacturers’ Institute) sanctioned maximum pressures.
This comparison is not totally objective since the 8 mm Remington Magnum
and .325 WSM
operate at 448.16 MPa (65000 psi), the 8x68mm S at 440 MPa (58740 psi), the 8x64mm S
at 405 MPa (58740 psi) and the 7.92x57mm Mauser
at 390 MPa (56564 psi) maximum chamber pressure. Higher chamber pressure results in higher muzzle velocities.
.375 Hölderlin maximum C.I.P. cartridge dimensions. All sizes in millimetres (mm).
Americans would define the shoulder angle at alpha/2 ≈ 14.53 degrees. The common rifling
twist rate for this cartridge is 305 mm (1 in 12 in), 6 grooves, Ø lands = 9.30 mm, Ø grooves = 9.55 mm, land width = 2.92 mm and the primer type
is large rifle magnum.
The .375 Hölderlin has 5.65 ml (87 grains
) H2O cartridge case capacity. According to the official C.I.P. guidelines the .375 Hölderlin case can handle up to 440 MPa (63,816 psi) piezo pressure.
According to the creator of the .375 Hölderlin, Mr. C. Otterbein, the idea behind the .375 Hölderlin was to develop a big game cartridge based on a German cartridge case for standard sized Mauser 98 bolt action rifles. The ballistic performance had to be close to or equal the performance of the .375 Holland & Holland Magnum
. The 8x68mm S was chosen as parent case, since it offers enough case capacity and a competent gunsmith can relatively easy rechamber a standard Mauser 98 rifle to accept 8x68mm S based cartridges. To keep costs down and promote an acceptable recoil level blowing out the parent case was renounced.
) or its American equivalent, SAAMI
(Sporting Arms and Ammunition Manufacturers’ Institute) are generally known as wildcats
. By blowing out standard factory cases the wildcatter generally hopes to gain extra muzzle velocity by increasing the case capacity of the factory parent cartridge case by a few percent. Practically there can be some muzzle velocity gained by this method, but the measured results between parent cartridges and their 'improved' wildcat offspring is often marginal. Besides changing the shape and internal volume of the parent cartridge case, wildcatters also can change the original caliber. A reason to change the original caliber can be to comply with a minimal permitted caliber or bullet weight for the legal hunting of certain species of game.
Wildcats are not governed by C.I.P. or SAAMI rules so wildcatters can capitalize the achievable high operating pressures. It is often reported that modern 68 mm RWS brass can tolerate up to 500 MPa (72519 psi) piezo pressure. Because the 8x68mm S offers an exceptional sturdy, pressure resistant cartridge case that can relatively easily be reloaded with primers, powder and bullets and hence be reused several times it has become quite popular amongst wildcatters. With the 8x68mm S as the parent case wildcatters have created .25x68, .270x68, 7x68mm, .30x68, .338x68, .375x68 or .416x68 variants. Improved or blown out 68 mm cartridge designs are reported to come performance wise close to the 8 mm Remington Magnum
which has about 14% more case capacity then the standard 8x68mm S.
Examples of 8x68mm S based wildcats are the relatively well known American 7 mm and .30 caliber Boo Boo and 7 mm and .30 HV wildcats. The Boo Boo wildcats were developed for long range target shooting where participants usually handload their ammunition
. Several 1,000 yard shooting competitions have been won with Boo Boo wildcats. A wildcat from Europe that uses the 8x68mm S as its parent case is the .30 Kovacs. It was designed in 1996 by Stefan Kovács, Austria-7041 Wulkaprodersdorf. The .30 Kovacs has much more powder-room (longer L2, wider P2, 40 degree Ackley-shoulder) then its parental case. It falls powder-room-wise between the .300 Winchester Magnum
and .300 Weatherby Magnum
but has energy and velocity falling between .300 Weatherby Magnum
and the .300 Remington Ultra Magnum
. This wildcat cartridge will be fitted only by Büchsenmachermeister Egon Kriebernegg. Another European wildcat based on the 8x68mm S is the .300 Styria Magnum. It was developed by Ing. Michael W. Mayerl from the Styria Arms company in Austria in 2005 as a reliable beltless high power cartridge for Mauser 98 rifles. The parent case is shortened to 65 mm (2.559 in) case length and necked down to 7.82 mm (.308 in) calibre. The shoulder angle is the same as the 8x68mm S so fire forming is not necessary and no new headspace gages are needed. The development goal of this cartridge was to get a highly reliable .30-calibre magnum cartridge that fits in the standard Mauser 98 action without any modification of the feeding lips, follower, feeding ramp or magazine length. Only the bolt face must be opened to a diameter of 13.3 mm (0.524 in). The throat of the .300 Styria Magnum is similar to the proven .308 Winchester
and short enough to seat the bullets to the lands without exceeding the maximum length of 84.8 mm (3.339 in) to fit the original Mauser 98 magazine. The thick walled 8x68mm S parent case manufactured by RWS can handle a usage piezo pressure up to 460 MPa (66717 psi).
Rim (firearms)
A rim is an external flange that is machined, cast, molded, stamped or pressed around the bottom of a firearms cartridge. The rim may serve a number of purposes, the most common being as the place for the extractor to engage...
bottlenecked rifle
Rifle
A rifle is a firearm designed to be fired from the shoulder, with a barrel that has a helical groove or pattern of grooves cut into the barrel walls. The raised areas of the rifling are called "lands," which make contact with the projectile , imparting spin around an axis corresponding to the...
cartridge
Cartridge (firearms)
A cartridge, also called a round, packages the bullet, gunpowder and primer into a single metallic case precisely made to fit the firing chamber of a firearm. The primer is a small charge of impact-sensitive chemical that may be located at the center of the case head or at its rim . Electrically...
(the S means it is intended for 8.2 mm (.323 in) groove diameter bullets) and its necked down sister cartridge
Cartridge (firearms)
A cartridge, also called a round, packages the bullet, gunpowder and primer into a single metallic case precisely made to fit the firing chamber of a firearm. The primer is a small charge of impact-sensitive chemical that may be located at the center of the case head or at its rim . Electrically...
the 6.5x68mm
6.5x68mm
The 6.5x68mm rimless bottlenecked rifle cartridge and its sister cartridge the 8x68mm S were developed in the 1930s by Mr...
(no S, or anything else, required) were developed in the 1930s by Mr. Schüler of the August Schüler Waffenfabrik, Suhl, Germany as magnum hunting cartridges that would just fit and function in standard sized Mauser 98 bolt action rifles. This is one of the early examples where a de novo rifle cartridge
Cartridge (firearms)
A cartridge, also called a round, packages the bullet, gunpowder and primer into a single metallic case precisely made to fit the firing chamber of a firearm. The primer is a small charge of impact-sensitive chemical that may be located at the center of the case head or at its rim . Electrically...
(the 8x68mm S and 6.5x68mm have no other cartridge as parent case) was developed by a gunsmith
Gunsmith
A gunsmith is a person who repairs, modifies, designs, or builds firearms. This occupation is different from an armorer. The armorer primarily maintains weapons and limited repairs involving parts replacement and possibly work involving accurization...
to fit a specific popular and widespread type of rifle.
History
The German ammunitionAmmunition
Ammunition is a generic term derived from the French language la munition which embraced all material used for war , but which in time came to refer specifically to gunpowder and artillery. The collective term for all types of ammunition is munitions...
manufacturer RWS (Rheinisch-Westfälischen Sprengstoff factories) introduced both cartridges commercially in the spring of 1939. With the official certification of the .375 Hölderlin this German 68 mm "family" of magnum rifle cartridges that all share the same basic cartridge case got expanded 68 years later.
The cartridges in this German 68 mm cartridge "family" are, in the order of development:
- 8x68mm S (1939)
- 6.5x68mm6.5x68mmThe 6.5x68mm rimless bottlenecked rifle cartridge and its sister cartridge the 8x68mm S were developed in the 1930s by Mr...
(1939) - .375 Hölderlin (2007)
The M 98 bolt actions of standard military Mauser 98 rifles have to be adapted by a competent gunsmith
Gunsmith
A gunsmith is a person who repairs, modifies, designs, or builds firearms. This occupation is different from an armorer. The armorer primarily maintains weapons and limited repairs involving parts replacement and possibly work involving accurization...
to function properly with these magnum cartridges since they are longer and the cases have a larger diameter than the 8x57mm service cartridges. In properly adapted standard military Gewehr 98
Gewehr 98
The Gewehr 98 is a German bolt action Mauser rifle firing the 8x57mm cartridge from a 5 round internal clip-loaded magazine that was the German service rifle from 1898 to 1935, when it was replaced by the Karabiner 98k. It was hence the main rifle of the German infantry during World War I...
or Karabiner 98k
Karabiner 98k
The Karabiner 98 Kurz was a bolt action rifle chambered for the 8x57mm IS/7.92×57mm IS cartridge that was adopted as the standard service rifle in 1935 by the German Wehrmacht. It was one of the final developments in the long line of Mauser military rifles...
service rifles the large 8x68mm S cartridges are however praised for very smooth and reliable feeding.
The widespread availability of standard size Mauser 98 rifles and the fact that the .375 H&H Magnum
.375 H&H Magnum
The .375 Holland & Holland Magnum is a powerful rifle round and one of the best-known and most popular medium-bore cartridges in the world. The .375 H&H was only the second cartridge ever to feature a belt, now common among magnum rounds. A popular misconception is that the belt is for headspace,...
cartridge and its necked down version the .300 H&H Magnum
.300 H&H Magnum
The .300 H&H Magnum Cartridge was introduced by the British company Holland & Holland as the Super-Thirty in June, 1925. The case was belted like the .375 H&H Magnum, and is based on the same case, as also is the .244 H&H Magnum. The belt is for headspace as the cases' shoulders have a narrow...
with approximately 72.4 mm case length were too long to fit in standard sized Mauser 98 bolt action rifles makes the shorter 8x68mm S, 6.5x68mm and .375 Hölderlin interesting chambering options.
World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
spoiled the commercial introduction and spread of the 8x68mm S amongst German hunters. The cartridge became due to its high performance and flat trajectory
Trajectory
A trajectory is the path that a moving object follows through space as a function of time. The object might be a projectile or a satellite, for example. It thus includes the meaning of orbit—the path of a planet, an asteroid or a comet as it travels around a central mass...
popular after World War II when German hunters were allowed again to own and hunt with full bore rifles. The 8x68mm S performance also made that hunters who had problems with handling magnum cartridge recoil stepped down to less powerful but for German conditions adequate medium cartridges like the 8x57mm IS, 7x64mm
7x64mm
The 7x64mm is a rimless bottlenecked centerfire cartridge developed for hunting. As is customary in European cartridges the 7 denotes the 7 mm bullet caliber and the 64 denotes the case length...
(Brenneke) or .30-06 Springfield
.30-06 Springfield
The .30-06 Springfield cartridge or 7.62×63mm in metric notation, was introduced to the United States Army in 1906 and standardized, and was in use until the 1960s and early 1970s. It replaced the .30-03, 6 mm Lee Navy, and .30 US Army...
(also known as the 7.62x63mm in metric countries). Recoil sensitive shooters can fit an efficient muzzle brake
Muzzle brake
Muzzle brakes and recoil compensators are devices that are fitted to the muzzle of a firearm or cannon to redirect propellant gases with the effect of countering both recoil of the gun and unwanted rising of the barrel during rapid fire...
to significantly reduce the amount of recoil. With the help of a muzzle brake the 8x68mm S recoil is reduced to tolerable levels.
Cartridge dimensions
Extremely thick brass results in 'only' 5.58 mlLitre
pic|200px|right|thumb|One litre is equivalent to this cubeEach side is 10 cm1 litre water = 1 kilogram water The litre is a metric system unit of volume equal to 1 cubic decimetre , to 1,000 cubic centimetres , and to 1/1,000 cubic metre...
(86 grains
Grain (measure)
A grain is a unit of measurement of mass that is nominally based upon the mass of a single seed of a cereal. From the Bronze Age into the Renaissance the average masses of wheat and barley grains were part of the legal definition of units of mass. However, there is no evidence of any country ever...
) H2O cartridge case capacity for the 8x68mm S. A rare feature of this German rimless bottlenecked centerfire cartridge design is that it has a slightly rebated rim
Rim (firearms)
A rim is an external flange that is machined, cast, molded, stamped or pressed around the bottom of a firearms cartridge. The rim may serve a number of purposes, the most common being as the place for the extractor to engage...
(P1 - R1 = 0.3 mm). A sign of the era in which the 8x68mm S was developed are the gently sloped shoulders. The exterior shape of the case was designed to promote reliable case feeding and extraction in bolt action rifles, under extreme conditions.
8x68mm S maximum C.I.P. cartridge dimensions. All sizes in millimetres (mm).
Americans would define the shoulder angle at alpha/2 ≈ 14.53 degrees. The common rifling
Rifling
Rifling is the process of making helical grooves in the barrel of a gun or firearm, which imparts a spin to a projectile around its long axis...
twist rate for this cartridge is 280 mm (1 in 11.02 in), 4 grooves, Ø lands = 7.89 mm, Ø grooves = 8.20 mm, land width = 4.40 mm and the primer type
Percussion cap
The percussion cap, introduced around 1830, was the crucial invention that enabled muzzleloading firearms to fire reliably in any weather.Before this development, firearms used flintlock ignition systems which produced flint-on-steel sparks to ignite a pan of priming powder and thereby fire the...
is large rifle magnum.
According to the official C.I.P. (Commission Internationale Permanente pour l'Epreuve des Armes à Feu Portatives
Commission Internationale Permanente pour l'Epreuve des Armes à Feu Portatives
The Commission Internationale Permanente pour l'Epreuve des Armes à Feu Portatives is an international organisation whose members are 14 states, mainly European....
) guidelines the 8x68mm S case can handle up to 440 MPa (63817 psi) 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.
The American .325 WSM
.325 WSM
.325 Winchester Short Magnum is an 8 mm caliber rebated rim bottlenecked centerfire short magnum cartridge that was introduced in 2005 by Winchester...
cartridge introduced in 2005 is probably the closest ballistic twin of the 8x68mm S. The .325 WSM is considerably shorter and fatter and has a more radical rebated rim (P1 -R 1 = 0.51 mm), much steeper shoulder angle (70 degrees / 35 degrees for Americans) and a shorter neck (7.82 mm). This makes the 8x68mm S case with its 9.11 mm long neck better suited for loading long heavier bullets and due to its sleeker exterior shape bound to cycle more reliably in bolt action rifles in extreme situations.
The 8x68mm S in field use
German big gameBig game hunting
Big game hunting is the hunting of large game. The term is historically associated with the hunting of Africa's Big Five game , and with tigers and rhinos on the Indian subcontinent. In North America, animals such as bears and bison were hunted...
hunters often use 8x68mm S rifles in Africa for hunting plains game
Plains game
Plains game is well established in literature and conversation as the sporting hunter's generic term for all those fair-game species of antelope and gazelle which are to be found - typically in rather open plains or savanna habitats - throughout sub-Saharan Africa...
, where American hunters would choose one of the .30 or .338 magnum cartridges. The 8x68mm S as a pure civil cartridge can be used in countries which ban civil use of former or current military ammunition.
Since there are not many factory loads available RWS currently (2007) offers 5 factory loads) and due to its good field reputation and efficiency, the 8x68mm S is often used by reload
Reload
Reload may refer to:* Repeated handloading of firearm cartridges, adding powder and primer to an empty metallic shell casing to create ammunition* Reloading scam...
ers. They have used this cartridge extensively to create powerful loads by handloading
Handloading
Handloading or reloading is the process of loading firearm cartridges or shotgun shells by assembling the individual components , rather than purchasing completely assembled, factory-loaded cartridges...
. Whilst staying within the 440 MPa C.I.P. limit a 8x68mm S rifle with a 650 mm (25.59 in) long barrel and appropriate modern gun propellants (Vihtavuori N560) can be handloaded to propel a 12.96 gram (200 gr) 8 mm bullet like the Sierra MatchKing to a muzzle velocity of 927 m/s (3042 ft/s).
The 8x68mm S has a good long range accuracy reputation i.e. it is not hard to develop or find loads that will shoot 1 MoA or better out of decent standard mass produced rifles. Factory 8x68mm S rifles often have a 650 mm or 26 in barrel with a 280 mm (1 in 11 in) twist rate, which works well in daily life. This twist rate was chosen since the bullet jackets used in the 1930s were not strong enough to cope with the forces generated by the magnum muzzle velocities of the 8x68mm S. The 240 mm (1 in 9.45 in) twist rate normally found in the 8x57mm IS makes the 8x68mm S combined with modern bullets with jackets designed for magnum cartridges an excellent long range cartridge.
Reloaders use the 8x68mm S as a utility cartridge on all European game from fox
Fox
Fox is a common name for many species of omnivorous mammals belonging to the Canidae family. Foxes are small to medium-sized canids , characterized by possessing a long narrow snout, and a bushy tail .Members of about 37 species are referred to as foxes, of which only 12 species actually belong to...
, roe deer
Roe Deer
The European Roe Deer , also known as the Western Roe Deer, chevreuil or just Roe Deer, is a Eurasian species of deer. It is relatively small, reddish and grey-brown, and well-adapted to cold environments. Roe Deer are widespread in Western Europe, from the Mediterranean to Scandinavia, and from...
and chamois
Chamois
The chamois, Rupicapra rupicapra, is a goat-antelope species native to mountains in Europe, including the Carpathian Mountains of Romania, the European Alps, the Tatra Mountains, the Balkans, parts of Turkey, and the Caucasus. The chamois has also been introduced to the South Island of New Zealand...
upwards to the big European game like red deer
Red Deer
The red deer is one of the largest deer species. Depending on taxonomy, the red deer inhabits most of Europe, the Caucasus Mountains region, Asia Minor, parts of western Asia, and central Asia. It also inhabits the Atlas Mountains region between Morocco and Tunisia in northwestern Africa, being...
, moose
Moose
The moose or Eurasian elk is the largest extant species in the deer family. Moose are distinguished by the palmate antlers of the males; other members of the family have antlers with a dendritic configuration...
and brown bear
Brown Bear
The brown bear is a large bear distributed across much of northern Eurasia and North America. It can weigh from and its largest subspecies, the Kodiak Bear, rivals the polar bear as the largest member of the bear family and as the largest land-based predator.There are several recognized...
. These people realized that bullets with different characteristics can be utilized to produce varying effects on game. They also realized that from 8 mm caliber upwards the rise of sectional density and penetrating capability of practical spin stabilized rifle bullets (bullets up to 5 to 5.5 calibers in length) tends to flatten out.
This means that loaded with light, short and soft nosed 8 mm bullets the 8x68mm S can be used on remarkably small game. Loaded with heavy, long and hard (solid copper alloy) bullets the 8x68mm S offers enough speed derived power to penetrate heavy and dangerous game. The 8x68mm S is suitable for hunting almost any game animal on the planet, though certain sub-Saharan Africa
Sub-Saharan Africa
Sub-Saharan Africa as a geographical term refers to the area of the African continent which lies south of the Sahara. A political definition of Sub-Saharan Africa, instead, covers all African countries which are fully or partially located south of the Sahara...
countries have a 9.53 mm (.375 in) minimum caliber rule for hunting Big Five game
Big Five game
The phrase Big Five game was coined by white hunters and refers to the five most difficult animals in Africa to hunt on foot. The term is still used in most tourist and wildlife guides that discuss African wildlife safaris. The collection consists of the lion, African elephant, cape buffalo,...
- i.e. leopard
Leopard
The leopard , Panthera pardus, is a member of the Felidae family and the smallest of the four "big cats" in the genus Panthera, the other three being the tiger, lion, and jaguar. The leopard was once distributed across eastern and southern Asia and Africa, from Siberia to South Africa, but its...
, lion
Lion
The lion is one of the four big cats in the genus Panthera, and a member of the family Felidae. With some males exceeding 250 kg in weight, it is the second-largest living cat after the tiger...
, cape buffalo, rhinoceros
Rhinoceros
Rhinoceros , also known as rhino, is a group of five extant species of odd-toed ungulates in the family Rhinocerotidae. Two of these species are native to Africa and three to southern Asia....
and elephant
Elephant
Elephants are large land mammals in two extant genera of the family Elephantidae: Elephas and Loxodonta, with the third genus Mammuthus extinct...
. In the Central African Republic
Central African Republic
The Central African Republic , is a landlocked country in Central Africa. It borders Chad in the north, Sudan in the north east, South Sudan in the east, the Democratic Republic of the Congo and the Republic of the Congo in the south, and Cameroon in the west. The CAR covers a land area of about ,...
, where there are no ammunition
Ammunition
Ammunition is a generic term derived from the French language la munition which embraced all material used for war , but which in time came to refer specifically to gunpowder and artillery. The collective term for all types of ammunition is munitions...
limits for hunting Big Five game
Big Five game
The phrase Big Five game was coined by white hunters and refers to the five most difficult animals in Africa to hunt on foot. The term is still used in most tourist and wildlife guides that discuss African wildlife safaris. The collection consists of the lion, African elephant, cape buffalo,...
, the 8x68mm S is used successfully for hunting elephant
Elephant
Elephants are large land mammals in two extant genera of the family Elephantidae: Elephas and Loxodonta, with the third genus Mammuthus extinct...
.
8 mm cartridges compared
Maximum muzzle velocity comparison in % of the probably most proliferated European and American 8 mm rifle cartridges out of 650 mm (25.59 in) long barrels loaded with relatively light to heavy 8 mm bullets to their C.I.P. or SAAMISaami
Saami or SAAMI can stand for:*Sami people*Sami languages*Sporting Arms and Ammunition Manufacturers' Institute...
(Sporting Arms and Ammunition Manufacturers’ Institute) sanctioned maximum pressures.
| Bullet weight gram (grain) | 8.23 g (127 gr) | 9.72 g (150 gr) | 11.34 g (175 gr) | 12.96 g (200 gr) | 14.26 g (220 gr) | Case capacity (%) |
| 7.92x57mm Mauser (8 x 57 IS) | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 |
| 8x64mm S | 102.7 | 102.7 | 102.8 | 102.9 | 102.9 | 110.3 |
| .325 WSM | 108.7 | 109.1 | 109.0 | 109.3 | 111.1 | 131.7 |
| 8x68mm S | 108.4 | 108.5 | 108.7 | 110.5 | 112.3 | 136.5 |
| 8 mm Rem. Mag. | 111.9 | 112.3 | 114.5 | 115.3 | 116.0 | 157.1 |
This comparison is not totally objective since the 8 mm Remington Magnum
8 mm Remington Magnum
The 8mm Remington Magnum belted rifle cartridge was introduced by Remington Arms Company in 1978 as a new chambering for the model 700 BDL rifle. The 8 mm Remington Magnum's parent case is the .375 H&H Magnum...
and .325 WSM
.325 WSM
.325 Winchester Short Magnum is an 8 mm caliber rebated rim bottlenecked centerfire short magnum cartridge that was introduced in 2005 by Winchester...
operate at 448.16 MPa (65000 psi), the 8x68mm S at 440 MPa (58740 psi), the 8x64mm S
8x64mm S
The 8x64mm S is a rimless bottlenecked centerfire cartridge developed as a military service round for the German Army who never issued it...
at 405 MPa (58740 psi) and the 7.92x57mm Mauser
7.92x57mm Mauser
The 8×57mm IS is a rimless bottlenecked rifle cartridge. The 8×57mm IS was adopted by the German Empire in 1905, and was the German service cartridge in both World Wars...
at 390 MPa (56564 psi) maximum chamber pressure. Higher chamber pressure results in higher muzzle velocities.
The .375 Hölderlin
The 8x68mm S case has functioned as the parent case for the .375 Hölderlin (9.5x68mm), which is essentially a 9.53 mm (.375 caliber) necked-up version of the 8x68mm S. The wildcat status of the .375 Hölderlin ended in 2007 when it got C.I.P. certified and became an officially registered and sanctioned member of the German 68 mm "family" of magnum rifle cartridges. If the .375 Hölderlin will become available as factory ammunition, like the older cartridge "family" members (8x68mm S and 6.5x68mm), is still unknown..375 Hölderlin maximum C.I.P. cartridge dimensions. All sizes in millimetres (mm).
Americans would define the shoulder angle at alpha/2 ≈ 14.53 degrees. The common rifling
Rifling
Rifling is the process of making helical grooves in the barrel of a gun or firearm, which imparts a spin to a projectile around its long axis...
twist rate for this cartridge is 305 mm (1 in 12 in), 6 grooves, Ø lands = 9.30 mm, Ø grooves = 9.55 mm, land width = 2.92 mm and the primer type
Percussion cap
The percussion cap, introduced around 1830, was the crucial invention that enabled muzzleloading firearms to fire reliably in any weather.Before this development, firearms used flintlock ignition systems which produced flint-on-steel sparks to ignite a pan of priming powder and thereby fire the...
is large rifle magnum.
The .375 Hölderlin has 5.65 ml (87 grains
Grain (measure)
A grain is a unit of measurement of mass that is nominally based upon the mass of a single seed of a cereal. From the Bronze Age into the Renaissance the average masses of wheat and barley grains were part of the legal definition of units of mass. However, there is no evidence of any country ever...
) H2O cartridge case capacity. According to the official C.I.P. guidelines the .375 Hölderlin case can handle up to 440 MPa (63,816 psi) piezo pressure.
According to the creator of the .375 Hölderlin, Mr. C. Otterbein, the idea behind the .375 Hölderlin was to develop a big game cartridge based on a German cartridge case for standard sized Mauser 98 bolt action rifles. The ballistic performance had to be close to or equal the performance of the .375 Holland & Holland Magnum
.375 H&H Magnum
The .375 Holland & Holland Magnum is a powerful rifle round and one of the best-known and most popular medium-bore cartridges in the world. The .375 H&H was only the second cartridge ever to feature a belt, now common among magnum rounds. A popular misconception is that the belt is for headspace,...
. The 8x68mm S was chosen as parent case, since it offers enough case capacity and a competent gunsmith can relatively easy rechamber a standard Mauser 98 rifle to accept 8x68mm S based cartridges. To keep costs down and promote an acceptable recoil level blowing out the parent case was renounced.
Wildcats
Cartridges that are not officially registered with nor sanctioned by C.I.P. (Commission Internationale Permanente pour l'Epreuve des Armes à Feu PortativesCommission Internationale Permanente pour l'Epreuve des Armes à Feu Portatives
The Commission Internationale Permanente pour l'Epreuve des Armes à Feu Portatives is an international organisation whose members are 14 states, mainly European....
) or its American equivalent, SAAMI
Saami
Saami or SAAMI can stand for:*Sami people*Sami languages*Sporting Arms and Ammunition Manufacturers' Institute...
(Sporting Arms and Ammunition Manufacturers’ Institute) are generally known as wildcats
Wildcat cartridge
A wildcat cartridge, or wildcat, is a custom cartridge for which ammunition and firearms are not mass produced. These cartridges are often created in order to optimize a certain performance characteristic of an existing commercial cartridge.Developing and using wildcat cartridges does not...
. By blowing out standard factory cases the wildcatter generally hopes to gain extra muzzle velocity by increasing the case capacity of the factory parent cartridge case by a few percent. Practically there can be some muzzle velocity gained by this method, but the measured results between parent cartridges and their 'improved' wildcat offspring is often marginal. Besides changing the shape and internal volume of the parent cartridge case, wildcatters also can change the original caliber. A reason to change the original caliber can be to comply with a minimal permitted caliber or bullet weight for the legal hunting of certain species of game.
Wildcats are not governed by C.I.P. or SAAMI rules so wildcatters can capitalize the achievable high operating pressures. It is often reported that modern 68 mm RWS brass can tolerate up to 500 MPa (72519 psi) piezo pressure. Because the 8x68mm S offers an exceptional sturdy, pressure resistant cartridge case that can relatively easily be reloaded with primers, powder and bullets and hence be reused several times it has become quite popular amongst wildcatters. With the 8x68mm S as the parent case wildcatters have created .25x68, .270x68, 7x68mm, .30x68, .338x68, .375x68 or .416x68 variants. Improved or blown out 68 mm cartridge designs are reported to come performance wise close to the 8 mm Remington Magnum
8 mm Remington Magnum
The 8mm Remington Magnum belted rifle cartridge was introduced by Remington Arms Company in 1978 as a new chambering for the model 700 BDL rifle. The 8 mm Remington Magnum's parent case is the .375 H&H Magnum...
which has about 14% more case capacity then the standard 8x68mm S.
Examples of 8x68mm S based wildcats are the relatively well known American 7 mm and .30 caliber Boo Boo and 7 mm and .30 HV wildcats. The Boo Boo wildcats were developed for long range target shooting where participants usually handload their ammunition
Ammunition
Ammunition is a generic term derived from the French language la munition which embraced all material used for war , but which in time came to refer specifically to gunpowder and artillery. The collective term for all types of ammunition is munitions...
. Several 1,000 yard shooting competitions have been won with Boo Boo wildcats. A wildcat from Europe that uses the 8x68mm S as its parent case is the .30 Kovacs. It was designed in 1996 by Stefan Kovács, Austria-7041 Wulkaprodersdorf. The .30 Kovacs has much more powder-room (longer L2, wider P2, 40 degree Ackley-shoulder) then its parental case. It falls powder-room-wise between the .300 Winchester Magnum
.300 Winchester Magnum
The .300 Winchester Magnum is a popular, belted, bottlenecked magnum rifle cartridge that was introduced by Winchester Repeating Arms Company in 1963 as a member of the family of Winchester Magnum cartridges. The .300 Winchester Magnum is a magnum cartridge designed to fit in a standard length...
and .300 Weatherby Magnum
.300 Weatherby Magnum
The .300 Weatherby Magnum is a .30 caliber rifle cartridge created by Roy Weatherby in 1944 and produced by Weatherby. It has become the most popular of all the Weatherby cartridges.-Background:...
but has energy and velocity falling between .300 Weatherby Magnum
.300 Weatherby Magnum
The .300 Weatherby Magnum is a .30 caliber rifle cartridge created by Roy Weatherby in 1944 and produced by Weatherby. It has become the most popular of all the Weatherby cartridges.-Background:...
and the .300 Remington Ultra Magnum
.300 Remington Ultra Magnum
The .300 Remington Ultra Magnum, also known as the .300 Ultra Mag or .300 RUM is a 7.62 mm caliber rifle cartridge , 7.62x72mm, or .30 caliber rifle cartridge introduced by Remington Arms in 1999. The .300 Remington Ultra Magnum is one of the largest commercially available .30 caliber magnums...
. This wildcat cartridge will be fitted only by Büchsenmachermeister Egon Kriebernegg. Another European wildcat based on the 8x68mm S is the .300 Styria Magnum. It was developed by Ing. Michael W. Mayerl from the Styria Arms company in Austria in 2005 as a reliable beltless high power cartridge for Mauser 98 rifles. The parent case is shortened to 65 mm (2.559 in) case length and necked down to 7.82 mm (.308 in) calibre. The shoulder angle is the same as the 8x68mm S so fire forming is not necessary and no new headspace gages are needed. The development goal of this cartridge was to get a highly reliable .30-calibre magnum cartridge that fits in the standard Mauser 98 action without any modification of the feeding lips, follower, feeding ramp or magazine length. Only the bolt face must be opened to a diameter of 13.3 mm (0.524 in). The throat of the .300 Styria Magnum is similar to the proven .308 Winchester
.308 Winchester
The .308 Winchester is a rifle cartridge and is the commercial cartridge upon which the military 7.62x51mm NATO centerfire cartridge is based. The .308 Winchester was introduced in 1952, two years prior to the NATO adoption of the 7.62x51mm NATO T65...
and short enough to seat the bullets to the lands without exceeding the maximum length of 84.8 mm (3.339 in) to fit the original Mauser 98 magazine. The thick walled 8x68mm S parent case manufactured by RWS can handle a usage piezo pressure up to 460 MPa (66717 psi).