The .300 Remington Ultra Magnum, also known as the .300 Ultra Mag, 7.62×72mm or .300 RUM, is a 7.62 mm (.308 inch) rifle cartridge introduced by Remington Arms in 1999. The .300 Remington Ultra Magnum is one of the largest commercially available .30 caliber magnums currently being produced. It is a beltless, rebated rim cartridge, capable of handling all large North American game, as well as long-range shooting. Among commercially produced .30-caliber rifle chamberings, the .300 Remington Ultra Magnum is second only to the .30-378 Weatherby Magnum in cartridge-case capacity.
In the early 1980s Aubrey White and Noburo Uno of North American Shooting Systems (NASS) based in British Columbia Canada began experimenting with the full length .404 Jeffery by reducing the taper and necking it down to various calibers such as 7 mm, .308, 311, 338, 9.3 mm and .375. These cartridges were known variously as the Canadian Magnum or the Imperial Magnums. Rifles were built on Remington Model 700 Long Actions and used McMillan stocks. Cartridges were fire formed from .404 Jeffery cases[citation needed] with the rim turned down, taper reduced and featured sharp shoulders.
Both Remington and Dakota Arms purchased the brass designed by Noburo Uno for use in their own experimentation and cartridge development. In 1999 Remington released the first of a series of cartridges virtually identical to the Canadian Magnum cartridges which featured a slightly wider body, increased taper, and shallower shoulders and named it the .300 Remington Ultra Magnum. Dakota too released their own version of the cartridge but chose not to turn down the rim and shortened the case to work in a standard length action. Remington would go on to design their own shortened versions of the Ultra Magnum cartridge which they were to call the Remington Short Action Ultra Magnum or RSAUM for short.
Design & SpecificationEdit
The .300 Remington Ultra Magnum is a member of the Remington Ultra Magnum cartridge family based on the .404 Jeffery via the Canadian Magnum cartridges. As these cartridges feature wider bodies than the belted magnums based on the .375 H&H case, these cartridges have greater case capacities than their corresponding full length belted Magnum cartridges such as the 7 mm Shooting Times Westerner, the .300 Weatherby Magnum, .340 Weatherby Magnum and the .375 Ackley Improved.
The .300 RUM features a rebated rim much like the .300 Canadian Magnum so as to allow the cartridge to function in the Remington M700 action without having to increase the bolt and bolt face diameter of the action. Unlike the belted Magnum cases based on the .375 H&H Magnum cartridge, the .300 RUM does not have a belt. All things being equal, a beltless cartridge would feed more reliably and more smoothly than a belted cartridge. Furthermore, as this is a beltless cartridge headspacing is designed to take place on the shoulder, which is considered beneficial by some as it is thought to promote accuracy and prolong case life of the cartridge. As modern belted magnums such as 7mm Remington Magnum and .300 Winchester Magnum actually headspace on the shoulder despite retaining the belt found on their parent cartridge, belted or unbelted is basically irrelevant in discussions of modern cartridges, and particularly so in discussions of unbelted cartridges.
SAAMI compliant .300 Remington Ultra Magnum cartridge schematic: All dimensions in inches [millimeters].
SAAMI recommends that the barrel have a 6 groove contour with a twist rate of one revolution in 10 in (250 mm). The barrel is to have a groove width of .115 in (2.9 mm). Bore is given as .300 in (7.6 mm) and a groove is .308 in (7.8 mm). Maximum case overflow capacity is 122.5 gr. of water (7.30 cm3). SAAMI recommended Maximum Average Pressure is set at 65,000 psi (4,500 bar).
Remington's ultra magnum cases were made wider than the .404 Jeffery case by .006 in (0.15 mm). The brass was made thicker so as to withstand the higher pressure of the new cartridge as the Jeffery cartridge had a maximum average pressure rating of 3,650 bar (52,900 psi).
Remington ammunition for the .300 RUM is available in three Power Levels. Power Level I duplicates the .30-06 Springfield, Power Level II that of the .300 Winchester Magnum and Power Level III is the full power load. Remington offers the full power (Power Level III) .300 Remington Ultra Magnum ammunition in 150 gr (9.7 g) at 3,450 ft/s (1,050 m/s), the 180 gr (12 g) at 3,250 ft/s (990 m/s) and the 200 gr (13 g) at 3,032 ft/s (924 m/s). These are among the highest velocities attained by a .30 caliber production rifle cartridge.
Performance Characteristics .300 Remington Ultra Magnum Power Level III Ammunition
Cartridge
Criteria
Muzzle
100-yard (91 m)
200-yard (180 m)
300-yard (270 m)
400-yard (370 m)
500-yard (460 m)
Premier Scirocco Bonded 150 grains (9.7 g) PR300UM5[2]
Velocity
3,450 ft/s (1,050 m/s)
3,211 ft/s (979 m/s)
2,985 ft/s (910 m/s)
2,769 ft/s (844 m/s)
2,564 ft/s (782 m/s)
2,369 ft/s (722 m/s)
Energy
3,964 ft⋅lbf (5,374 J)
3,434 ft⋅lbf (4,656 J)
2,967 ft⋅lbf (4,023 J)
2,554 ft⋅lbf (3,463 J)
2,190 ft⋅lbf (2,970 J)
1,869 ft⋅lbf (2,534 J)
Bullet Drop
−1.5 in (−3.8 cm)
2.6 in (6.6 cm)
3.2 in (8.1 cm)
0 in (0 cm)
−7.8 in (−20 cm)
−20.9 in (−53 cm)
Premier Scirocco Bonded 180 grains (12 g) PR300UM3[2]
Rifle sighted in 1.5 inch (2.5 cm) above bore axis. Altitude 1000 ft. Temperature 59 °F (15 °C). Values courtesy of Big Game Info Ballistic Calculator
The .300 RUM is an excellent long range cartridge with the ability to deliver a useful level of energy downrange especially with the power level III ammunition. Due to its high velocity it exhibits less bullet drop than most other .30 caliber (7.62 mm) cartridges.
Compared to other production .30 caliber (7.62 mm) cartridges, only the .30-378 Weatherby Magnum surpasses the .300 Remington Ultra Magnum. Factory loaded .30-378 Weatherby Magnum ammunition has a 150–200 ft/s (46–61 m/s) velocity advantage over the .300 RUM cartridge with any given bullet weight. However, the .30-378 Weatherby Magnum is considered the most overbore production sporting cartridge available and is not considered as efficient as the .300 RUM cartridge. In part due to its excessive freebore lengths the claimed velocities by Weatherby is a resultant factor of this freebore length. If chambered to allow bullets to seat to the lands of the rifling the large Weatherby cartridges would exhibit overpressure signs immediately. All things equal the .300 RUM and .30-378 Weatherby if chambered with the same throat and freebore would be comparable. Known freebore lengths of older Weatherby rifles have been in excess of 1 inch. The .30-378 is one of the most extreme cases of overbore and has among the highest throat erosion levels of any rifles.
Sporting UsageEdit
The .300 Remington Ultra Magnum cartridge was conceived as a long range hunting cartridge and in this it exceeds most other cartridges. It is able to launch heavy bullets with high sectional densities at high velocities thereby retaining energy to take game cleanly at longer ranges than less powerful cartridges such as the.30-06 Springfield and even the .300 Winchester Magnum.
^(PDF). Archived from the original (PDF) on September 28, 2007. Retrieved August 17, 2007.
^ abc. remington.com. Remington. January 8, 2011. Archived from the original on June 2, 2011. Retrieved January 13, 2011.
October 21, 2023
remington, ultra, magnum, this, article, needs, additional, citations, verification, please, help, improve, this, article, adding, citations, reliable, sources, unsourced, material, challenged, removed, find, sources, news, newspapers, books, scholar, jstor, j. This article needs additional citations for verification Please help improve this article by adding citations to reliable sources Unsourced material may be challenged and removed Find sources 300 Remington Ultra Magnum news newspapers books scholar JSTOR January 2013 Learn how and when to remove this template message The 300 Remington Ultra Magnum also known as the 300 Ultra Mag 7 62 72mm or 300 RUM is a 7 62 mm 308 inch rifle cartridge introduced by Remington Arms in 1999 The 300 Remington Ultra Magnum is one of the largest commercially available 30 caliber magnums currently being produced It is a beltless rebated rim cartridge capable of handling all large North American game as well as long range shooting Among commercially produced 30 caliber rifle chamberings the 300 Remington Ultra Magnum is second only to the 30 378 Weatherby Magnum in cartridge case capacity 300 Remington Ultra Magnum 300 RUM cartridgeTypeRiflePlace of originCanadaProduction historyDesignerRemingtonDesigned1999ManufacturerRemington Arms CompanyProduced1999 presentSpecificationsParent case 404 JefferyCase typecartridge center fire primer bottleneckBullet diameter 308 in 7 8 mm Neck diameter 344 in 8 7 mm Shoulder diameter 525 in 13 3 mm Base diameter 550 in 14 0 mm Rim diameter 534 in 13 6 mm Case length2 850 in 72 4 mm Overall length3 600 in 91 4 mm Case capacity110 2 gr H2O 7 14 cm3 Rifling twist1 10 Primer typeLarge rifle magnumMaximum pressure65 000 psi 450 MPa Ballistic performanceBullet mass type Velocity Energy150 gr 10 g X 3 456 ft s 1 053 m s 3 979 ft lbf 5 395 J 168 gr 11 g BTHP 3 295 ft s 1 004 m s 4 051 ft lbf 5 492 J 180 gr 12 g BTSP 3 229 ft s 984 m s 4 168 ft lbf 5 651 J 200 gr 13 g SP 3 067 ft s 935 m s 4 178 ft lbf 5 665 J 220 gr 14 g RN 2 933 ft s 894 m s 4 203 ft lbf 5 699 J Test barrel length 24 610 mm Source s Accurate Powder 1 Contents 1 Origin amp History 2 Design amp Specification 3 Performance 4 Sporting Usage 5 See also 6 ReferencesOrigin amp History EditIn the early 1980s Aubrey White and Noburo Uno of North American Shooting Systems NASS based in British Columbia Canada began experimenting with the full length 404 Jeffery by reducing the taper and necking it down to various calibers such as 7 mm 308 311 338 9 3 mm and 375 These cartridges were known variously as the Canadian Magnum or the Imperial Magnums Rifles were built on Remington Model 700 Long Actions and used McMillan stocks Cartridges were fire formed from 404 Jeffery cases citation needed with the rim turned down taper reduced and featured sharp shoulders Both Remington and Dakota Arms purchased the brass designed by Noburo Uno for use in their own experimentation and cartridge development In 1999 Remington released the first of a series of cartridges virtually identical to the Canadian Magnum cartridges which featured a slightly wider body increased taper and shallower shoulders and named it the 300 Remington Ultra Magnum Dakota too released their own version of the cartridge but chose not to turn down the rim and shortened the case to work in a standard length action Remington would go on to design their own shortened versions of the Ultra Magnum cartridge which they were to call the Remington Short Action Ultra Magnum or RSAUM for short Design amp Specification EditThe 300 Remington Ultra Magnum is a member of the Remington Ultra Magnum cartridge family based on the 404 Jeffery via the Canadian Magnum cartridges As these cartridges feature wider bodies than the belted magnums based on the 375 H amp H case these cartridges have greater case capacities than their corresponding full length belted Magnum cartridges such as the 7 mm Shooting Times Westerner the 300 Weatherby Magnum 340 Weatherby Magnum and the 375 Ackley Improved The 300 RUM features a rebated rim much like the 300 Canadian Magnum so as to allow the cartridge to function in the Remington M700 action without having to increase the bolt and bolt face diameter of the action Unlike the belted Magnum cases based on the 375 H amp H Magnum cartridge the 300 RUM does not have a belt All things being equal a beltless cartridge would feed more reliably and more smoothly than a belted cartridge Furthermore as this is a beltless cartridge headspacing is designed to take place on the shoulder which is considered beneficial by some as it is thought to promote accuracy and prolong case life of the cartridge As modern belted magnums such as 7mm Remington Magnum and 300 Winchester Magnum actually headspace on the shoulder despite retaining the belt found on their parent cartridge belted or unbelted is basically irrelevant in discussions of modern cartridges and particularly so in discussions of unbelted cartridges nbsp SAAMI compliant 300 Remington Ultra Magnum cartridge schematic All dimensions in inches millimeters SAAMI recommends that the barrel have a 6 groove contour with a twist rate of one revolution in 10 in 250 mm The barrel is to have a groove width of 115 in 2 9 mm Bore is given as 300 in 7 6 mm and a groove is 308 in 7 8 mm Maximum case overflow capacity is 122 5 gr of water 7 30 cm3 SAAMI recommended Maximum Average Pressure is set at 65 000 psi 4 500 bar Remington s ultra magnum cases were made wider than the 404 Jeffery case by 006 in 0 15 mm The brass was made thicker so as to withstand the higher pressure of the new cartridge as the Jeffery cartridge had a maximum average pressure rating of 3 650 bar 52 900 psi Performance Edit nbsp left to right 308 Winchester 30 06 Springfield 300 Weatherby Magnum 300 Remington Ultra MagnumRemington ammunition for the 300 RUM is available in three Power Levels Power Level I duplicates the 30 06 Springfield Power Level II that of the 300 Winchester Magnum and Power Level III is the full power load Remington offers the full power Power Level III 300 Remington Ultra Magnum ammunition in 150 gr 9 7 g at 3 450 ft s 1 050 m s the 180 gr 12 g at 3 250 ft s 990 m s and the 200 gr 13 g at 3 032 ft s 924 m s These are among the highest velocities attained by a 30 caliber production rifle cartridge Performance Characteristics 300 Remington Ultra Magnum Power Level III Ammunition Cartridge Criteria Muzzle 100 yard 91 m 200 yard 180 m 300 yard 270 m 400 yard 370 m 500 yard 460 m Premier Scirocco Bonded 150 grains 9 7 g PR300UM5 2 Velocity 3 450 ft s 1 050 m s 3 211 ft s 979 m s 2 985 ft s 910 m s 2 769 ft s 844 m s 2 564 ft s 782 m s 2 369 ft s 722 m s Energy 3 964 ft lbf 5 374 J 3 434 ft lbf 4 656 J 2 967 ft lbf 4 023 J 2 554 ft lbf 3 463 J 2 190 ft lbf 2 970 J 1 869 ft lbf 2 534 J Bullet Drop 1 5 in 3 8 cm 2 6 in 6 6 cm 3 2 in 8 1 cm 0 in 0 cm 7 8 in 20 cm 20 9 in 53 cm Premier Scirocco Bonded 180 grains 12 g PR300UM3 2 Velocity 3 250 ft s 990 m s 3 051 ft s 930 m s 2 860 ft s 870 m s 2 677 ft s 816 m s 2 502 ft s 763 m s 2 334 ft s 711 m s Energy 4 221 ft lbf 5 723 J 3 719 ft lbf 5 042 J 3 268 ft lbf 4 431 J 2 864 ft lbf 3 883 J 2 501 ft lbf 3 391 J 2 177 ft lbf 2 952 J Bullet Drop 1 5 in 3 8 cm 2 9 in 7 4 cm 3 6 in 9 1 cm 0 in 0 cm 8 5 in 22 cm 22 5 in 57 cm Premier A Frame 200 grains 13 g RS300UM2 2 Velocity 3 032 ft s 924 m s 2 793 ft s 851 m s 2 566 ft s 782 m s 2 352 ft s 717 m s 2 148 ft s 655 m s 1 954 ft s 596 m s Energy 4 082 ft lbf 5 534 J 3 464 ft lbf 4 697 J 2 924 ft lbf 3 964 J 2 456 ft lbf 3 330 J 2 049 ft lbf 2 778 J 1 695 ft lbf 2 298 J Bullet Drop 1 5 in 3 8 cm 3 7 in 9 4 cm 4 5 in 11 cm 0 in 0 cm 10 8 in 27 cm 29 2 in 74 cm Rifle sighted in 1 5 inch 2 5 cm above bore axis Altitude 1000 ft Temperature 59 F 15 C Values courtesy of Big Game Info Ballistic CalculatorThe 300 RUM is an excellent long range cartridge with the ability to deliver a useful level of energy downrange especially with the power level III ammunition Due to its high velocity it exhibits less bullet drop than most other 30 caliber 7 62 mm cartridges Compared to other production 30 caliber 7 62 mm cartridges only the 30 378 Weatherby Magnum surpasses the 300 Remington Ultra Magnum Factory loaded 30 378 Weatherby Magnum ammunition has a 150 200 ft s 46 61 m s velocity advantage over the 300 RUM cartridge with any given bullet weight However the 30 378 Weatherby Magnum is considered the most overbore production sporting cartridge available and is not considered as efficient as the 300 RUM cartridge In part due to its excessive freebore lengths the claimed velocities by Weatherby is a resultant factor of this freebore length If chambered to allow bullets to seat to the lands of the rifling the large Weatherby cartridges would exhibit overpressure signs immediately All things equal the 300 RUM and 30 378 Weatherby if chambered with the same throat and freebore would be comparable Known freebore lengths of older Weatherby rifles have been in excess of 1 inch The 30 378 is one of the most extreme cases of overbore and has among the highest throat erosion levels of any rifles Sporting Usage EditThe 300 Remington Ultra Magnum cartridge was conceived as a long range hunting cartridge and in this it exceeds most other cartridges It is able to launch heavy bullets with high sectional densities at high velocities thereby retaining energy to take game cleanly at longer ranges than less powerful cartridges such as the 30 06 Springfield and even the 300 Winchester Magnum See also EditList of rifle cartridges Table of handgun and rifle cartridges 7 mm caliberReferences Edit 300 RUM data at Accurate Powder PDF Archived from the original PDF on September 28 2007 Retrieved August 17 2007 a b c 300 Remington Ultra Mag Power Level Ammunition remington com Remington January 8 2011 Archived from the original on June 2 2011 Retrieved January 13 2011 Retrieved from https en wikipedia org w index php title 300 Remington Ultra Magnum amp oldid 1179843467, wikipedia, wiki, book, books, library,
