.25 Winchester Super Short Magnum

.25 WSSM
25 WSSM cartridge comparison AR-15.jpg
25 WSSM cartridges loaded for an AR-15 magazine. For comparison, a 2 3/4" shotgun shell & 5.56mm NATO cartridge are included
Place of originUSA
Production history
DesignerBrowning / Winchester
Parent case.300 WSM
Bullet diameter.257 in (6.5 mm)
Neck diameter.305 in (7.7 mm)
Shoulder diameter.544 in (13.8 mm)
Base diameter.555 in (14.1 mm)
Rim diameter.535 in (13.6 mm)
Rim thickness.054 in (1.4 mm)
Case length1.670 in (42.4 mm)
Overall length2.362 in (60.0 mm)
Primer typelarge rifle
Maximum pressure (transducer)65,000 psi
Ballistic performance
Bullet mass/type Velocity Energy
75 gr (5 g) VMax 3,775 ft/s (1,151 m/s) 2,374 ft⋅lbf (3,219 J)
85 gr (6 g) BT 3,547 ft/s (1,081 m/s) 2,375 ft⋅lbf (3,220 J)
100 gr (6 g) BT 3,264 ft/s (995 m/s) 2,366 ft⋅lbf (3,208 J)
115 gr (7 g) BT 2,999 ft/s (914 m/s) 2,297 ft⋅lbf (3,114 J)
120 gr (8 g) SP 2,985 ft/s (910 m/s) 2,375 ft⋅lbf (3,220 J)
Source(s): Hodgdon Online Reload Data

The .25 Winchester Super Short Magnum is a third member of the Winchester Super Short Magnum (WSSM) cartridge family created by Winchester and Browning. It is the largest caliber of the WSSM line (excluding wildcats) and is the most capable of handling large game such as deer and wild boar.


The 25 WSSM has similar ballistics to the .25-06 but in a much shorter case.

It is a necked-up version of the .243 WSSM,[1] which is in turn a shortened .300 WSM (Winchester Short Magnum). The WSSM cartridges are based on ballistics design philosophies that are intended to produce a high level of efficiency.[2]

Like other WSSM cases, the .25 is short and fat, which is designed to be more efficient.

Unlike the other WSSM rounds, the .25 is a magnum in name only, based on the case it uses. Performance wise it is a clone of the .25-06 Remington, making it well suited for medium to large game.[3] The 25 WSSM provides the same performance as the 25-06 Remington, with the advantage of having lighter short action rifles. Having the short fat design, the cartridge loads burn at a more consistent rate, providing a higher level of accuracy. Performance is far less than other .25 caliber magnum rounds as the .257 Weatherby Magnum. In fact, ballistically it's almost identical to the improved version of the .257 Roberts, which P.O. Ackley said was his favorite choice for an all-around cartridge.[4]

See also[]


  1. ^ * The .25 WSSM by Chuck Hawks
  2. ^ "Browning WSSM info". Archived from the original on 2010-12-24. Retrieved 2010-05-04.
  3. ^ The Overlooked .25 Caliber Cartridges by Chuck Hawks
  4. ^ Handbook for Shooters & Reloaders vol I, Book by P.O. Ackley; Plaza Publishing, 1962, ISBN 978-99929-4-881-1

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