.257 Roberts
Encyclopedia
The .257 Roberts a medium powered .25 caliber
cartridge
known affectionately as the Bob. It has been described as the best compromise between the low recoil
and flat trajectory
of smaller calibers such as the .22
and 6mm
, and the strong energy but not the strong recoil of larger popular hunting calibers, such as the 7mm
family and the popular .30-06.
available at that time. Ned Roberts
is usually credited with being the designer for this cartridge idea. Eventually in 1934 Remington Arms
chose to introduce their own commercial version of such a cartridge, and although it wasn't the exact dimensions of the wildcat made by Roberts, they called it the .257 Roberts.
From its introduction until the appearance of more popular 6mm cartridges such as .243 Winchester
and 6 mm Remington
), it was a very popular general purpose cartridge. Today, although overshadowed by other cartridges, it lives on with bolt-action
rifles being available from some major manufacturers.
Arisaka
rifles brought to the United States
as wartime souvenir
s were sometimes converted by rechambering to utilize more readily available .257 Roberts cartridge cases because commercially produced 6.5x50mm Arisaka cartridges were scarce prior to distribution by Norma Projektilfabrik A/S
. The neck of the Roberts case would be slightly enlarged to accept handloaded
6.5mm bullets. The modified Roberts cases are sometimes known as 6.5x.257 Roberts, although the case headstamp
may still indicate .257 Roberts. Neither unmodified .257 Roberts ammunition nor the original 6.5x50mm Arisaka ammunition are suitable for firing in rechambered Arisaka rifles.
.
as a low-pressure round. At the time there were many older actions available of questionable strength. With a modern action and handloading, this cartridge is capable of markedly improved performance.
One of the common improvements is called the .257 Roberts(+P) which has a SAAMI
maximum pressure limit of 58,000 PSI compared to the 54,000 PSI listed for the standard .257 Roberts.
P.O. Ackley said that the .257 Roberts Ackley Improved was probably the most useful all-around cartridge. The Ackley Improved was a typical change of a steeper shoulder coupled with blown-out sides for more of a straight cartridge, providing greater powder capacity.
Caliber
In guns including firearms, caliber or calibre is the approximate internal diameter of the barrel in relation to the diameter of the projectile used in it....
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...
known affectionately as the Bob. It has been described as the best compromise between the low 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 flat trajectory
Trajectory
A trajectory is the path that a moving object follows through space as a function of time. The object might be a projectile or a satellite, for example. It thus includes the meaning of orbit—the path of a planet, an asteroid or a comet as it travels around a central mass...
of smaller calibers such as the .22
5 mm caliber
This 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.All measurements are in mm .-Rimfire cartridges:...
and 6mm
6 mm caliber
This article lists firearm cartridges which have a bullet caliber between and .*Length refers to the cartridge case length.*OAL refers to the overall length of the cartridge.All measurements are in mm .-Pistol cartridges:-.24in :...
, and the strong energy but not the strong recoil of larger popular hunting calibers, such as the 7mm
7 mm caliber
This 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....
family and the popular .30-06.
History
Many cartridge designers in the 1920s were creating various .25 caliber cartridges. Because of its size, the 7x57mm Mauser case was a common choice, having near the ideal volume capacity for the "quarter-bore" (called this because the .25 caliber is one quarter of an inch) using powdersSmokeless 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...
available at that time. Ned Roberts
Ned Roberts
Edward 'Ned' John Roberts was a Welsh international rugby union fullback who played club rugby for Llanelli and international rugby for Wales.-Rugby career:...
is usually credited with being the designer for this cartridge idea. Eventually in 1934 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....
chose to introduce their own commercial version of such a cartridge, and although it wasn't the exact dimensions of the wildcat made by Roberts, they called it the .257 Roberts.
From its introduction until the appearance of more popular 6mm cartridges such as .243 Winchester
.243 Winchester
The .243 Winchester is a popular sporting rifle cartridge. Initially designed as a varmint round, it is now more frequently used on medium to large game such as whitetail deer, mule deer, pronghorn, wild hogs, and even black bear and caribou...
and 6 mm Remington
6 mm Remington
The 6mm Remington was introduced by Remington Arms Company in 1955 as the .244 Remington. It is based on necking down the .257 Roberts. Originally intended as a Varmint and predator cartridge, the .244 was never factory loaded with bullets over 90 grains. Rifles marked .244 Remington have a 1 in ...
), it was a very popular general purpose cartridge. Today, although overshadowed by other cartridges, it lives on with bolt-action
Bolt-action
Bolt action is a type of firearm action in which the weapon's bolt is operated manually by the opening and closing of the breech with a small handle, most commonly placed on the right-hand side of the weapon...
rifles being available from some major manufacturers.
Conversion of war-souvenir Japanese Arisaka rifles
Japanese Type 38Type 38 rifle
The is a bolt-action rifle. For a time it was the standard rifle of the Japanese infantry. It was known also as the Type 38 Year Meiji Carbine in Japan. An earlier, similar weapon was the Type 30 Year Meiji Rifle, which was also used alongside it. Both of these weapons were also known as the...
Arisaka
Arisaka
Arisaka is a family of Japanese military bolt action rifles, in production from approximately 1898, when it replaced the Murata rifle, until the end of World War II in 1945...
rifles brought to the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
as wartime souvenir
Souvenir
A souvenir , memento, keepsake or token of remembrance is an object a person acquires for the memories the owner associates with it. The term souvenir brings to mind the mass-produced kitsch that is the main commodity of souvenir and gift shops in many tourist traps around the world...
s were sometimes converted by rechambering to utilize more readily available .257 Roberts cartridge cases because commercially produced 6.5x50mm Arisaka cartridges were scarce prior to distribution by Norma Projektilfabrik A/S
Norma (company)
Norma Precision is a Swedish manufacturer of ammunition located in Åmotfors, in the province of Värmland, just 20 km of the Norwegian border. It is commonly referred to as simply Norma.- History :...
. The neck of the Roberts case would be slightly enlarged to accept handloaded
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...
6.5mm bullets. The modified Roberts cases are sometimes known as 6.5x.257 Roberts, although the case headstamp
Headstamp
A headstamp is the markings on the bottom of a cartridge case designed for a firearm. It usually tells who manufactured the case. If it is a civilian case it often also tells the caliber, if it is military, the year of manufacture is often added....
may still indicate .257 Roberts. Neither unmodified .257 Roberts ammunition nor the original 6.5x50mm Arisaka ammunition are suitable for firing in rechambered Arisaka rifles.
Performance
With light bullets the .257 produces little recoil and has a flat trajectory suitable for varmint hunting. With heavier bullets it is capable of taking all but the largest North American game animals. The original factory load for this is very similar to the .250-3000 Savage.250-3000 Savage
The .250-3000 Savage is a rifle cartridge created by Charles Newton in 1915 and is also known as the .250 Savage. The name comes from its original manufacturer, Savage Arms and the fact that the original load achieved a 3000 ft/s velocity with an 87 grain bullet.-Background:Charles Newton...
.
Improved Cartridges
Remington introduced the commercial version of this popular wildcatWildcat cartridge
A wildcat cartridge, or wildcat, is a custom cartridge for which ammunition and firearms are not mass produced. These cartridges are often created in order to optimize a certain performance characteristic of an existing commercial cartridge.Developing and using wildcat cartridges does not...
as a low-pressure round. At the time there were many older actions available of questionable strength. With a modern action and handloading, this cartridge is capable of markedly improved performance.
One of the common improvements is called the .257 Roberts(+P) which has a SAAMI
Saami
Saami or SAAMI can stand for:*Sami people*Sami languages*Sporting Arms and Ammunition Manufacturers' Institute...
maximum pressure limit of 58,000 PSI compared to the 54,000 PSI listed for the standard .257 Roberts.
P.O. Ackley said that the .257 Roberts Ackley Improved was probably the most useful all-around cartridge. The Ackley Improved was a typical change of a steeper shoulder coupled with blown-out sides for more of a straight cartridge, providing greater powder capacity.
Comparison
| cartridge | Bullet Weight | Muzzle Velocity (ft/sec) | Muzzle Energy (ft·lbf) |
|---|---|---|---|
| .250-3000 Savage .250-3000 Savage The .250-3000 Savage is a rifle cartridge created by Charles Newton in 1915 and is also known as the .250 Savage. The name comes from its original manufacturer, Savage Arms and the fact that the original load achieved a 3000 ft/s velocity with an 87 grain bullet.-Background:Charles Newton... |
100 | 2864 | 1822 |
| .257 Roberts | 100 | 2898 | 1865 |
| .257 Roberts (+P) | 100 | 3048 | 2063 |
| .257 Roberts Ackley Improved | 100 | 3279* | 2388* |
| .25 WSSM .25 WSSM The .25 Winchester Super Short Magnum is a third member of the Winchester Super Short Magnum cartridge family created by Winchester and Browning. It is the largest caliber of the WSSM's and is the most capable of handling large game such as deer and wild boar.It is a necked-up version of the .243... |
100 | 3264 | 2366 |
| .25-06 Remington .25-06 Remington The .25-06 Remington had been a wildcat cartridge for half a century before being standardized by Remington in 1969. It is based on the .30-06 Springfield cartridge necked-down to .257 inch caliber with no other changes... |
100 | 3283 | 2394 |
| .257 Weatherby Magnum .257 Weatherby Magnum The .257 Weatherby Magnum is a .25 Caliber belted bottlenecked cartridge. It is one of the original standard length magnums developed by shortening the .375 H&H Magnum case to approx.... |
100 | 3512* | 2839* |
- using a 26" barrel.