.256 Winchester Magnum

Cartridge Data Published On: December 20, 2014 at 11:36 pm by Bullet-Blog and last updated on February 12, 2015 at 11:24 am


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The .256 Winchester Magnum is a Center Fire cartridge with a Bullet Diameter of 0.257 in” (6.53mm) that is primarily used in Pistols and Rifles. The .256 Winchester Magnum originated in The United States in 1960. The .256 Winchester Magnum also has a case length of 1.3 in” (33.02mm) and an overall length of 1.53 in” (38.86mm).


The .256 Winchester Magnum, often referred to as the .256 WinMag, was originally conceived by Winchester back in the early 1960s for use in various Sturm/Ruger and Marlin firearms, including the original Hawkeye Pistol. The .256 Winchester Magnum was created using a .357 Magnum cartridge and necking it down to accept .257 diameter projectile, mostly for varminting or target use. Because of its moderate case capacity and high pressures from the bottleneck cartridge, the .256 Winchester Magnum is capable of velocities well above 1450fps using a 50 grain projectile and offers modest muzzle energies in the 250-350 ft lbs range.

Cartridge Details

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  • 1960
  • The United States
  • Rimmed,Bottleneck
  • Pistols
  • 0.257 in” (6.53mm)
  • 0.285 in” (7.24mm)
  • 0.368 in” (9.35mm)
  • 0.381 in” (9.68mm)
  • 0.44 in” (11.18mm)
  • 0.06 in” (1.52mm)
  • 1.3 in” (33.02mm)
  • 1.53 in” (38.86mm)
  • 22 gr H20 (1.43 cm3)
  • Center Fire (Small Pistol)
  • 50000 psi (345 MPa)
  • 340 MPa (49313 psi)
  • ~442 MPa (64107 psi)

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