The 7mm Remington Ultra Magnum or 7mm RUM is a 7mm 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...

 introduced by Remington Arms

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....

 in 2001.

Overview

The 7mm RUM was created using 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...

 case which was also used to develop the .375 RUM .300 RUM, and .338 RUM. By necking down the .300 RUM to suit the .284 or 7mm projectile, Remington produced a non-belted case with a head diameter that is somewhat larger than belt diameter of original belted numbers. The resulting case has significantly more capacity than any conventional belted magnum. Compared to the 7mm Remington Magnum, top 7mm RUM loads deliver 25% more energy at 300 yards. Such performance demands a price and in this case, that is a large muzzle blast, sharp recoil and short barrel life.