.256 Winchester Magnum

Last updated
.256 Winchester Magnum
256magnum.png
TypeHandgun, rifle
Place of originUnited States
Production history
DesignerRuger, Winchester
Designed1960
ManufacturerWinchester
Produced1961
Specifications
Parent case .357 Magnum
Case typeRimmed, Bottlenecked
Bullet diameter.257 in (6.5 mm)
Neck diameter.285 in (7.2 mm)
Shoulder diameter.368 in (9.3 mm)
Base diameter.381 in (9.7 mm)
Rim diameter.440 in (11.2 mm)
Rim thickness.060 in (1.5 mm)
Case length1.281 in (32.5 mm)
Overall length1.590 in (40.4 mm)
Case capacity22  gr H2O (1.4 cm3)
Rifling twist1 in 14 in (360 mm)
Primer typeSmall pistol
Maximum pressure50,000 psi (340 MPa)
Ballistic performance
Bullet mass/typeVelocityEnergy
60 gr (4 g) FMJ2,350 ft/s (720 m/s)735 ft⋅lbf (997 J)
60 gr (4 g) JHP*2,760 ft/s (840 m/s)1,015 ft⋅lbf (1,376 J)
Test barrel length: 8.5" * 24"

The .256 Winchester Magnum is a firearms cartridge developed by Winchester, and was produced by necking-down a .357 Magnum cartridge to .257 diameter. It was designed for shooting small game and varmints.

Contents

History

Introduced in 1960, Winchester offered ammo and reloading components into the early 1990s. The cartridge was first chambered in the Ruger Hawkeye single shot pistol. The next year (1962) Marlin chambered their Model 62 Levermatic rifle for the new Winchester cartridge. These were the two principal firearms chambered for the .256 Win. Mag. It is now obsolete and only offered as a chambering by custom manufacturers of single-shot firearm barrels such as Match Grade Machine and Bullberry. Previously, the Thompson Center Custom Shop had produced some, before closing its doors in 2010.

Ballistics

From an 8.5 inch pistol barrel the 60 grain .256 Winchester factory load was advertised as having a MV of 2350 fps and ME of 735 ft. lbs. This was 250 fps faster and nearly twice as powerful as the .22 Remington Jet, a varmint cartridge for revolvers that was also based on a necked-down .357 Magnum case.

According to data from the fifth edition of the Hornady Handbook of Cartridge Reloading, handloaders with a .256 rifle can approximately duplicate the Winchester factory load using the Hornady 60 grain Flat Point bullet in front of 15.5 grains of H4227 powder for a MV of 2700 fps. The trajectory of that load looks like this: +2.3 inches at 50 yards, +4.4 inches at 100 yards, 0 at 200 yards, and -26.2 inches at 300 yards.

Winchester offered factory loaded .256 Magnum ammunition (and brass to reloaders) into the beginning of the 1990s. Winchester .256 factory loads used a 60 grain Open Point Expanding bullet at a MV of 2760 fps and ME of 1015 ft. lbs. from a 24-inch rifle barrel. That is about 500 fps faster than Winchester factory loads for the old .25-20 cartridge. At 200 yards the velocity was 1542 fps and the remaining energy was 317 ft. lbs.

Firearms

The .256 Winchester Magnum was chambered in a very small selection of firearms, and never achieved great commercial success. [1] Its firearms included:

The 256 Winchester Magnum is also chambered occasionally in custom-built revolvers. Past candidates for this caliber conversion have included Ruger Old Model and New Model Blackhawks, [2] and Smith & Wesson K-frames (Models 10, 14, 15, and 19). [3] Colt produced one Python in this caliber as a prototype and retains it in their museum. [4]

See also

Related Research Articles

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.243 Winchester

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.270 Winchester Rifle cartridge

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.17 HMR

.17 Hornady Magnum Rimfire, commonly known as the .17 HMR, is a rimfire rifle cartridge developed by the ammunition company Hornady in 2002. It was developed by necking down a .22 Magnum case to take a .17 caliber (4.5 mm) projectile. Commonly loaded with a 17 grain projectile, it can deliver muzzle velocities in excess of 775 m/s (2,650 ft/s).

7mm-08 Remington Necked down .308Win

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.32 H&R Magnum

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Super magnum

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6.5mm Creedmoor Centerfire rifle cartridge

The 6.5mm Creedmoor (6.5×48 mm), designated 6.5 Creedmoor by SAAMI, 6.5 Creedmoor by the C.I.P. or 6.5 CM or 6.5 CRDMR for short, is a centerfire rifle cartridge introduced by Hornady in 2007. It was developed by Hornady senior ballistics scientist Dave Emary in partnership with Dennis DeMille, the vice-president of product development at Creedmoor Sports, hence the name. The cartridge is a necked-down modification of the .30 Thompson Center.

Varmint rifle

Varmint rifle is an American English term for a small-caliber precision firearm or high-powered airgun primarily used for both varmint hunting and pest control. These tasks include killing three types of pests or nuisance animals that spread diseases or destroy crops or livestock:

.500 S&W Magnum Revolver cartridge designed by Cor-bon and Smith & Wesson (S&W)

The .500 S&W Magnum or 12.7×41mmSR is a .50 caliber semi-rimmed revolver cartridge developed by Cor-Bon in partnership with the Smith & Wesson "X-Gun" engineering team for use in the Smith & Wesson Model 500 X-frame revolver and introduced in February 2003 at the SHOT Show. It has two primary design purposes: as a hunting handgun cartridge capable of taking all North American game species, and to be the most powerful production handgun cartridge to date. To put the cartridge’s extreme level of power into perspective; the muzzle energy of a .500 S&W bullet fired from a typical commercial loading of the round is roughly equivalent to that of a 16 pound bowling ball traveling at a speed of over 70 mph.

.17 Winchester Super Magnum

.17 Winchester Super Magnum, is a rimfire rifle cartridge developed by the ammunition company Winchester in 2012. It descended from the .27 caliber nail-gun blank by necking down the blank case to take a .17 caliber (4.5 mm) bullet. Initial loadings were with a 20-grain bullet, delivering muzzle velocities around 3,000 ft/s.

References

  1. Ayoob, Massad. "What will be your top self-defense sellers for 2004?(Lethal Force)." Shooting Industry. Publishers' Development Corporation. 2003: http://www.highbeam.com/doc/1G1-111971507.html Archived 2015-11-07 at the Wayback Machine
  2. "+ BCA Catalog + Ruger Single Action Basic Caliber Conversions".
  3. "+ BCA Catalog + Small-bore Caliber Conversions".
  4. Association, National Rifle. "American Rifleman | Official Journal Of The NRA | A Look Back at the Colt Python". American Rifleman | Official Journal Of The NRA. Retrieved 2021-06-17.