.300 H&H Magnum
Encyclopedia
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 slope rather than an actual shoulder. More modern magnums continue this practice, but headspacing on the belt is not necessary with their more sharply angled shoulders. The cartridge won the 1000-yard Wimbledon Cup Match at Camp Perry in 1935, and the international 1,000 yard competition in 1937. Winchester
chambered the Model 70
in .300 Holland & Holland
Magnum
in 1937.
The cartridge offered superior Ballistics
to the .30-06 for long range, and the .300 H&H is almost as versatile with all bullet weights and types, especially if well-developed handloads
are used. It excels with the heaviest .30-calibre bullets in the 180–220-grain range. SAAMI has set the pressure limit for this cartridge at 54,000 P.S.I. Its case length calls for a full-length magnum action, and surplus military actions chambered for the .308 Norma Magnum
or the .300 Winchester Magnum
offered a lower cost alternative for similar ballistics in the 1960s. The long .300 H&H case was designed for loading cordite
, and those two modern magnum cartridges offered similar powder volume in a shorter case better adapted to ballistic uniformity with United States
Improved Military Rifle (IMR)
smokeless powder
.
It has never been as popular as the .30-'06; but the mystique of well-crafted rifles chambered for the .300 H&H keeps the cartridge in use despite its repeatedly reported demise. The .300 H&H is a fine African plains game
cartridge, and suitable for all but the most dangerous big game and pachyderm
s.
treats the .300 H&H Magnum and the .30 Super Belted Rimless H&H as separate entities and provides separate entries for the cartridges. There are minute but significant variations with regard to dimensions between the two cartridges. While both cartridges are regulated by the CIP only the chamber of the .300 H&H Magnum is regulated by the CIP. The CIP does not provide chamber dimensions for the .30 Super.
Although cartridges are generally considered interchangeable, chambers conforming to the strict minimum chamber of the .30 Super may not be able to chamber the .300 H&H Magnum.
Both cartridges are based on .375 H&H Magnum cartridge design which provides an increase in capacity over many other cartridges. They feature tapering bodies and very shallow shoulders which prevent them from headspacing reliably on their shoulders. The belt plays a useful role in these cartridges in that it provides a demarcation point for reliable headspacing of the cartridge.
Significantly the shoulder vertex calculated by the CIP for both cartridges is given as 91.69 mm (3.6 in) for both cartridges. As the CIP uses the shoulder vertex length as an index to provide correct headspacing for the cartridge, this indicates that the cartridges are dimensionally interchangeable. However, as the .30 Super is rated for a lower pressure, the .300 H&H Magnum cartridge should not be fired in a .30 Super. However, the .30 Super can be discharged in a .300 H&H Magnum rifle. As most significant difference between the cartridges was that the .30 Super was loaded to a far lower pressure than the .300 H&H Magnum. The .30 Super drove a 180 gr bullet at 2750 ft/s (838.2 m/s) while the .300 H&H Magnum was loaded with the same bullet at 2920 ft/s (890 m/s).
Holland & Holland
Holland & Holland is a British gun-maker based in London, England. They offer hand-made sporting rifles and shotguns. H&H holds two Royal Warrants.-History:Holland & Holland was founded by Harris Holland in the year 1835....
as the Super-Thirty in June, 1925. The case was belted like 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,...
, and is based on the same case, as also is the .244 H&H Magnum
.244 H&H Magnum
The .244 Holland & Holland Magnum cartridge was created in 1955 in Great Britain by deerstalker and rifle-maker David Lloyd of Pipewell Hall, Northamptonshire and Glencassley in Sutherland, Scotland, and is not to be confused with the smaller-cased and much milder 6 mm Remington...
. The belt is for headspace as the cases' shoulders have a narrow slope rather than an actual shoulder. More modern magnums continue this practice, but headspacing on the belt is not necessary with their more sharply angled shoulders. The cartridge won the 1000-yard Wimbledon Cup Match at Camp Perry in 1935, and the international 1,000 yard competition in 1937. Winchester
Winchester Repeating Arms Company
The Winchester Repeating Arms Company was a prominent American maker of repeating firearms, located in New Haven, Connecticut. The Winchester brand is today used under license by two subsidiaries of the Herstal Group, Fabrique Nationale of Belgium and the Browning Arms Company of Morgan, Utah.-...
chambered the Model 70
Winchester Model 70
The Winchester Model 70 is a bolt action sporting rifle. It has an iconic place in American sporting culture and has been held in high regard by shooters since it was introduced in 1936, earning the moniker "The Rifleman's Rifle". The action has some design similarities to Mauser designs and it is...
in .300 Holland & Holland
Holland & Holland
Holland & Holland is a British gun-maker based in London, England. They offer hand-made sporting rifles and shotguns. H&H holds two Royal Warrants.-History:Holland & Holland was founded by Harris Holland in the year 1835....
Magnum
Magnum
Magnum may refer to several things:* Moses Magnum, a Marvel Comics villain*Magnum, P.I., a television series** Thomas Magnum, the lead character...
in 1937.
The cartridge offered superior Ballistics
Ballistics
Ballistics is the science of mechanics that deals with the flight, behavior, and effects of projectiles, especially bullets, gravity bombs, rockets, or the like; the science or art of designing and accelerating projectiles so as to achieve a desired performance.A ballistic body is a body which is...
to the .30-06 for long range, and the .300 H&H is almost as versatile with all bullet weights and types, especially if well-developed handloads
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...
are used. It excels with the heaviest .30-calibre bullets in the 180–220-grain range. SAAMI has set the pressure limit for this cartridge at 54,000 P.S.I. Its case length calls for a full-length magnum action, and surplus military actions chambered for the .308 Norma Magnum
.308 Norma Magnum
The .308 Norma Magnum cartridge was created by Nils Kvale at Norma, Sweden. Like the larger .358 Norma Magnum it is based on the .300 H&H Magnum. The length of the case is the longest that would fit in a standard Mauser action. While it appeared to have a bright future initially, it was soon...
or 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...
offered a lower cost alternative for similar ballistics in the 1960s. The long .300 H&H case was designed for loading cordite
Cordite
Cordite is a family of smokeless propellants developed and produced in the United Kingdom from 1889 to replace gunpowder as a military propellant. Like gunpowder, cordite is classified as a low explosive because of its slow burning rates and consequently low brisance...
, and those two modern magnum cartridges offered similar powder volume in a shorter case better adapted to ballistic uniformity with United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
Improved Military Rifle (IMR)
Improved Military Rifle (IMR)
Improved Military Rifle describes a series of tubular nitrocellulose smokeless powders evolved from World War I through World War II for loading military and commercial ammunition and sold to private citizens for reloading rifle ammunition for hunting and target shooting...
smokeless powder
Smokeless powder
Smokeless powder is the name given to a number of propellants used in firearms and artillery which produce negligible smoke when fired, unlike the older gunpowder which they replaced...
.
It has never been as popular as the .30-'06; but the mystique of well-crafted rifles chambered for the .300 H&H keeps the cartridge in use despite its repeatedly reported demise. The .300 H&H is a fine African 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...
cartridge, and suitable for all but the most dangerous big game and pachyderm
Pachydermata
Pachydermata is an obsolete order of mammals described by Gottlieb Storr, Georges Cuvier and others, at one time recognized by many systematists...
s.
Design & Specifications
The CIPCommission 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....
treats the .300 H&H Magnum and the .30 Super Belted Rimless H&H as separate entities and provides separate entries for the cartridges. There are minute but significant variations with regard to dimensions between the two cartridges. While both cartridges are regulated by the CIP only the chamber of the .300 H&H Magnum is regulated by the CIP. The CIP does not provide chamber dimensions for the .30 Super.
Although cartridges are generally considered interchangeable, chambers conforming to the strict minimum chamber of the .30 Super may not be able to chamber the .300 H&H Magnum.
Both cartridges are based on .375 H&H Magnum cartridge design which provides an increase in capacity over many other cartridges. They feature tapering bodies and very shallow shoulders which prevent them from headspacing reliably on their shoulders. The belt plays a useful role in these cartridges in that it provides a demarcation point for reliable headspacing of the cartridge.
- CIP compliant .300 H&H Magnum schematic diagram
- CIP compliant .30 Super schematic diagram
| Dimension / Specification | CIP Dimension Index | 300 H&H Magnum Value | .30 Super Value |
| Base to shoulder length | 53.46 mm (2.1 in) | 53.34 mm (2.1 in) | |
| Base to neck length | 62.96 mm (2.5 in) | 62.87 mm (2.5 in) | |
| Height to belt | 5.59 mm (0.22007874015748 in) | 5.56 mm (0.218897637795276 in) | |
| Extractor notch ∅ | 11.94 mm (0.47007874015748 in) | 11.61 mm (0.457086614173228 in) | |
| Extractor notch width | 0.94 mm (0.037007874015748 in) | 1.02 mm (0.0401574803149606 in) | |
| ∠ to belt | 35° | 45° | |
| Shoulder ∠ | 17° 0’ 9” | 16° 56’ 59” | |
| Pressure | 4300 bar (62,366.2 psi) | 3650 bar (52,938.8 psi) |
Significantly the shoulder vertex calculated by the CIP for both cartridges is given as 91.69 mm (3.6 in) for both cartridges. As the CIP uses the shoulder vertex length as an index to provide correct headspacing for the cartridge, this indicates that the cartridges are dimensionally interchangeable. However, as the .30 Super is rated for a lower pressure, the .300 H&H Magnum cartridge should not be fired in a .30 Super. However, the .30 Super can be discharged in a .300 H&H Magnum rifle. As most significant difference between the cartridges was that the .30 Super was loaded to a far lower pressure than the .300 H&H Magnum. The .30 Super drove a 180 gr bullet at 2750 ft/s (838.2 m/s) while the .300 H&H Magnum was loaded with the same bullet at 2920 ft/s (890 m/s).
See also
- .30-06 Springfield.30-06 SpringfieldThe .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...
- .300 Winchester Magnum.300 Winchester MagnumThe .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...
- .300 Weatherby Magnum.300 Weatherby MagnumThe .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:...
- .300 Winchester Short Magnum
- .300 Remington Short Action Ultra Magnum
- .300 Remington Ultra Magnum.300 Remington Ultra MagnumThe .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...
- 7 mm caliber7 mm caliberThis article lists firearm cartridges which have a bullet in the to caliber range.*Length refers to the cartridge case length.*OAL refers to the overall length of the cartridge....