The .300, .338, .375 family of Remington American Magnums was designed by Aleksandr Kolesnikov of Houston, Texas, USA in February 2010. This was a response to the .375 Ruger

.375 Ruger

The .375 Ruger is a rimless, standard-length rifle cartridge designed for the hunting of large dangerous game. It is designed to provide an increase in performance over the .375 H&H cartridge, yet to be chambered in a standard length action rifle...

. It is based upon the .300 RUM case, shortened to 2.580" to fit into Standard length Remington 700

Remington 700

The Model 700 series of firearms are bolt-action rifles manufactured by Remington Arms since 1962. All are based on the same centerfire bolt action. They often come with a 3, 4 or 5-round internal magazine depending on caliber, some of which have a floor-plate for quick-unloading, and some of which...

 action (firearm), while maximizing powder capacity by using .550" case diameter instead of Ruger's .532".

The RAM case family provides nearly the same performance as the RUM while generating less recoil

Recoil

Recoil is the backward momentum of a gun when it is discharged. In technical terms, the recoil caused by the gun exactly balances the forward momentum of the projectile and exhaust gasses, according to Newton's third law...

 and using less costly "standard" model 700 actions, rather than more expensive "magnum" actions. This offers a power level between the RUM and WSM cases, while employing sturdy, accurate, plentiful, relatively inexpensive 700 actions.

History

In 1999 Remington jumped on the current high performance bandwagon by creating their own beltless magnum

Belted magnum

The term belted magnum refers to any caliber cartridge, generally rifles, using a shell casing with a pronounced "belt" around its base that continues 2-4mm past the extractor groove. This design originated with the British gunmaker Holland & Holland for the purpose of headspacing certain of...

. The .300 RUM was the first in a family of new Ultra magnum cartridges 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...

, later joined by the 7 mm RUM

7 mm Remington Ultra Magnum

The 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...

, .338 RUM

.338 Remington Ultra Magnum

The .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...

, and .375 RUM

.375 Remington Ultra Magnum

The .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...

. In addition, Remington later created a shortened version called the Remington Short Action Ultra Magnums to compete with Winchester's

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.-...

 line of 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...

s.

Essentially a variant of the .375 Dakota

.375 Dakota

The .375 Dakota is dangerous game cartridge and was designed by Don Allen, the founder of Dakota Arms of Sturgis, South Dakota. Since the .375 Dakota is a proprietary cartridge, no other manufacturers have produced rifles or ammunition for the .375 Dakota cartridge...

, Aleksandr Kolesnikov named the .300 RAM in homage

Homage

Homage is a show or demonstration of respect or dedication to someone or something, sometimes by simple declaration but often by some more oblique reference, artistic or poetic....

 to the Remington Corporation. It is based on the .300 RUM

.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...

 shortened to fit in Remington 700

Remington 700

The Model 700 series of firearms are bolt-action rifles manufactured by Remington Arms since 1962. All are based on the same centerfire bolt action. They often come with a 3, 4 or 5-round internal magazine depending on caliber, some of which have a floor-plate for quick-unloading, and some of which...

-series Standard length actions. The acronym "RAM" is to specify that it is intended to be capable of taking any North or South American Game animals. Additionally, "RAM" alludes to the speeds attained by Ramjet

Ramjet

A ramjet, sometimes referred to as a stovepipe jet, or an athodyd, is a form of airbreathing jet engine using the engine's forward motion to compress incoming air, without a rotary compressor. Ramjets cannot produce thrust at zero airspeed and thus cannot move an aircraft from a standstill...

 aircraft engines.

The .300 RAM series cases utilize a larger case diameter than .375 Ruger based cartridge, while still fitting in Standard length Remington 700 action (firearm)

Firearm action

In firearms terminology, an action is the physical mechanism that manipulates cartridges and/or seals the breech. The term is also used to describe the method in which cartridges are loaded, locked, and extracted from the mechanism. Actions are generally categorized by the type of mechanism used...

.

Because the .300 RAM is beltless, it headspaces on the shoulder giving it a potential edge in accuracy over belted magnums

Belted magnum

The term belted magnum refers to any caliber cartridge, generally rifles, using a shell casing with a pronounced "belt" around its base that continues 2-4mm past the extractor groove. This design originated with the British gunmaker Holland & Holland for the purpose of headspacing certain of...

, in addition to longer case life. The 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...

 allows this cartridge to be used in an action with a magnum bolt faces (.535 inches).

Comparison

.300 Magnum performance comparisons

Cartridge	Bullet Weight	Muzzle velocity Muzzle velocity Muzzle velocity is the speed a projectile has at the moment it leaves the muzzle of the gun. Muzzle velocities range from approximately to in black powder muskets , to more than in modern rifles with high-performance cartridges such as the .220 Swift and .204 Ruger, all the way to for tank guns...	Muzzle energy Muzzle energy Muzzle energy is the kinetic energy of a bullet as it is expelled from the muzzle of a firearm. It is often used as a rough indication of the destructive potential of a given firearm or load...
.300 RSAUM	200	2790	3458
.300 WSM .300 WSM .300 Winchester Short Magnum is a thirty caliber rebated rim bottlenecked centerfire short magnum cartridge that was introduced in 2001 by Winchester. The cartridge overall length is 72.64mm, cartridge case is 53.34mm in length and the bullet diameter is .308 in , which is common to all U.S. .30...	200	2822	3538
.300 Win Mag .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...	200	2822	3538
7.62 Jonson	200	2935	3826
.300 Wby Mag .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:...	200	2987	3963
.300 RUM	200	3154	4419
.30-378 Wby Mag .30-378 Weatherby Magnum The .30-378 Weatherby Magnum is a cartridge introduced by Weatherby in 1996 that uses the same case as the previously existing .378 Weatherby Magnum and .460 Weatherby Magnum, necked down to a 30 caliber bullet. It is offered with bullets between 165 and 200 grains in factory loading, generating...	200	3160	4434
.300 Lapua Magnum .300 Lapua Magnum The .300 Lapua Magnum is a specialized rimless bottlenecked centerfire cartridge developed for long-range rifles. The commercially successful .338 Lapua Magnum cartridge has functioned as the parent case for the .300 Lapua Magnum, which is essentially a necked-down version of the .338 Lapua Magnum...	200	3200	4585