Remington Ultra Magnum
Encyclopedia
Remington Ultra Magnum, or RUM, refers to a "family" of cartridges developed in 1999 and the early 2000s by the Remington Arms
. All of the RUM cartridges are based on the .404 Jeffery
non-belted magnum cartridge. There is a long-case line, as well as a shortened version designed to fit a short rifle
action (such as a .308 Winchester
). The long case is very large and provides performance that exceeds existing commercial magnums, such as the .300 Winchester Magnum
and .300 Weatherby Magnum
.
The short design is the same idea as used in the Winchester Short Magnum
cartridges. The shorter cartridges are known as known as Remington Short Action Ultra Magnum, RSAUM, RSUM, or SAUM.
The RUM family of cartridges are Delta L problem
cartridges, meaning they can present unexpected chambering and/or feeding problems. The Delta L problem
article explains this problem in more detail.
line. Lazzeroni's short magnums (7.21 Lazzeroni
Firebird and Tomahawk) were designed to operate in a short-action rifle, instead of requiring a long action. The U.S. Repeating Arms Company was the first major manufacturer to commercialize Lazzeroni's concept, followed shortly thereafter by Remington
with their "Short Action Ultra Mag" line.
Remington Arms
Remington Arms Company, Inc. was founded in 1816 by Eliphalet Remington in Ilion, New York, as E. Remington and Sons. It is the oldest company in the United States which still makes its original product, and is the oldest continuously operating manufacturer in North America. It is the only U.S....
. All of the RUM cartridges are based on the .404 Jeffery
.404 Jeffery
The .404 Jeffery is a large caliber, rimless cartridge designed for large, dangerous game, such as the big five of Africa. Other names for this cartridge include .404 Jeffery Rimless, .404 Rimless Nitro Express, and 10.75 × 73 mm...
non-belted magnum cartridge. There is a long-case line, as well as a shortened version designed to fit a short 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...
action (such as a .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...
). The long case is very large and provides performance that exceeds existing commercial magnums, such as 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:...
.
The short design is the same idea as used in the Winchester Short Magnum
Winchester Short Magnum
Winchester Short Magnum, or WSM, refers to a family of rebated rim bottlenecked centerfire short magnum cartridges developed in the early 2000s by the U.S. Repeating Arms Company, the maker of Winchester rifles and one of the oldest firearms manufacturers in the United States...
cartridges. The shorter cartridges are known as known as Remington Short Action Ultra Magnum, RSAUM, RSUM, or SAUM.
The RUM family of cartridges are Delta L problem
Delta L problem
The delta L problem is a condition that occurs regarding certain firearms chambers and their practical incompatibility with ammunition made for the corresponding chambering....
cartridges, meaning they can present unexpected chambering and/or feeding problems. The Delta L problem
Delta L problem
The delta L problem is a condition that occurs regarding certain firearms chambers and their practical incompatibility with ammunition made for the corresponding chambering....
article explains this problem in more detail.
7.21 Lazzeroni
The RUM family is based on work done creating short magnums by John Lazzeroni, similar to the Winchester Short MagnumWinchester Short Magnum
Winchester Short Magnum, or WSM, refers to a family of rebated rim bottlenecked centerfire short magnum cartridges developed in the early 2000s by the U.S. Repeating Arms Company, the maker of Winchester rifles and one of the oldest firearms manufacturers in the United States...
line. Lazzeroni's short magnums (7.21 Lazzeroni
Lazzeroni cartridge
Lazzeroni cartridges are a range of extremely powerful proprietary magnum sporting rifle cartridges developed and manufactured since the early 1990s by US hunting enthusiast John Lazzeroni...
Firebird and Tomahawk) were designed to operate in a short-action rifle, instead of requiring a long action. The U.S. Repeating Arms Company was the first major manufacturer to commercialize Lazzeroni's concept, followed shortly thereafter by Remington
Remington Arms
Remington Arms Company, Inc. was founded in 1816 by Eliphalet Remington in Ilion, New York, as E. Remington and Sons. It is the oldest company in the United States which still makes its original product, and is the oldest continuously operating manufacturer in North America. It is the only U.S....
with their "Short Action Ultra Mag" line.
6 mm Benchrest
Another influence was a series of 6 mm cartridges developed for bench-rest target shooting competitions in the 1970s. The idea behind these cartridges was that a short, fat cartridge would be more "efficient" than the traditional long, narrow cartridge, as more of the powder column would be in the immediate vicinity of the primer as it detonated. In turn, this would mean that a cartridge of this type would be able to propel a bullet at speeds comparable to those of "magnum" cartridges of the same caliber using significantly less powder.RUM cartridges
The cartridges in this family are:- 7 mm Remington Ultra Magnum7 mm Remington Ultra MagnumThe 7mm Remington Ultra Magnum or 7mm RUM is a 7mm rifle cartridge introduced by Remington Arms in 2001.-Overview:The 7mm RUM was created using the .404 Jeffery case which was also used to develop the .375 RUM .300 RUM, and .338 RUM...
- .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...
also known as the .300 Ultra Mag or .300 RUM - .338 Remington Ultra Magnum.338 Remington Ultra MagnumThe .338 Remington Ultra Magnum is a .338 caliber rifle cartridge introduced by Remington Arms in 2002. It is a beltless, rebated rim cartridge based on the .300 Remington Ultra Magnum case shortened .090" loaded with a .338 caliber bullet...
- .375 Remington Ultra Magnum.375 Remington Ultra MagnumThe .375 Remington Ultra Magnum, also known as the .375 RUM is a .375 rifle cartridge introduced by Remington Arms in 2002. It is a beltless, rebated rim cartridge created by necking up the .300 Remington Ultra Magnum case to .375 caliber with no other changes. The .375 Remington Ultra Magnum is...