300 Winchester Short Magnum (also known as 300 WSM) is a .30
caliber
In guns, particularly firearms, but not #As a measurement of length, artillery, where a different definition may apply, caliber (or calibre; sometimes abbreviated as "cal") is the specified nominal internal diameter of the gun barrel Gauge ( ...
rebated rim
A rim is an external flange that is machined, cast, molded, stamped, or pressed around the bottom of a firearms cartridge. Thus, rimmed cartridges are sometimes called "flanged" cartridges. Almost all cartridges feature an extractor or headspaci ...
bottlenecked
centerfire
Two rounds of .357 Magnum, a centerfire cartridge; notice the circular primer in the center
A center-fire (or centerfire) is a type of metallic cartridge used in firearms, where the primer is located at the center of the base of its casing (i. ...
Winchester
Winchester (, ) is a City status in the United Kingdom, cathedral city in Hampshire, England. The city lies at the heart of the wider City of Winchester, a local government Districts of England, district, at the western end of the South Downs N ...
.The 300 WSM (Winchester Short Magnum) by Chuck Hawks (subscriptions req) /ref>
Specifications
The overall cartridge length is 72.6 mm. The cartridge case length is 53.34 mm. The bullet diameter is .308 in (7.82 mm), which is common to U.S. .30 caliber cartridges. The principle at work in the short magnum cartridge is the fitting of larger volumes of powder in closer proximity to the primer's flash hole, resulting in more-uniform ignition, thereby generating essentially the same ballistic performance as long-action magnums with less powder, and less recoil. The .300 WSM has a case capacity of 80 grains. The
.30-06 Springfield
The .30-06 Springfield cartridge (pronounced "thirty- aught-six" ), 7.62×63mm in metric notation, and called the .30 Gov't '06 by Winchester, was introduced to the United States Army in 1906 and later standardized; it remained in military us ...
30-30 Winchester
The .30-30 Winchester / 7.8x51mmR (officially named the .30 Winchester Center Fire or .30 WCF) cartridge was first marketed for the Winchester Model 1894 lever-action rifle in 1895..300 Winchester Magnum has a case capacity of 93.8 grains. While providing ballistic performance nearly identical to that of the .300 Winchester Magnum, 300 WSM does this with about 14 grains less powder. The .300 WSM also head-spaces off of the case shoulder, versus the older .300 Winchester Magnum's belted head space design.
The advantage to this round is the ballistic performance is nearly identical to the .300 Winchester Magnum in a lighter rifle with a shorter action burning 8 - 10% less gunpowder. A disadvantage of cartridge case designs with relatively large case head diameters lies in relatively high
bolt thrust
Bolt thrust or breech pressure is a term used in internal ballistics and firearms (whether small arms or artillery) that describes the amount of rearward force exerted by the propellant gases on the Bolt (firearms), bolt or Breechblock, breech of a ...
levels exerted on the locking mechanism of the employed firearm. Also, in small ring actions the larger chamber diameter removes more steel from the barrel tenon, making it weaker radially. The short, squat design of the cartridge also can cause feeding issues, especially in rifles whose magazine follower isn't at a very specific angle, leading to rounds not being properly fed out of the magazine and engaged by the bolt carrier.
Use
The .300 WSM is adequate for hunting all types of big game in
North America
North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...
including (but not limited to):
moose
The moose (: 'moose'; used in North America) or elk (: 'elk' or 'elks'; used in Eurasia) (''Alces alces'') is the world's tallest, largest and heaviest extant species of deer and the only species in the genus ''Alces''. It is also the tal ...
,
black bear
Black bear or Blackbear may refer to:
Animals
* American black bear (''Ursus americanus''), a North American bear species
* Asian black bear (''Ursus thibetanus''), an Asian bear species
Music
* Black Bear (band), a Canadian First Nations group
...
,
brown bear
The brown bear (''Ursus arctos'') is a large bear native to Eurasia and North America. Of the land carnivorans, it is rivaled in size only by its closest relative, the polar bear, which is much less variable in size and slightly bigger on av ...
,
elk
The elk (: ''elk'' or ''elks''; ''Cervus canadensis'') or wapiti, is the second largest species within the deer family, Cervidae, and one of the largest terrestrial mammals in its native range of North America and Central and East Asia. ...
,
black-tailed deer
Black-tailed deer or blacktail deer occupy coastal regions of western North America. There are two subspecies, the Columbian black-tailed deer (''Odocoileus hemionus columbianus'') which ranges from the Pacific Northwest of the United States and ...
,
mule deer
The mule deer (''Odocoileus hemionus'') is a deer indigenous to western North America; it is named for its ears, which are large like those of the mule. Two subspecies of mule deer are grouped into the black-tailed deer.
Unlike the related whit ...
, and
white-tailed deer
The white-tailed deer (''Odocoileus virginianus''), also known Common name, commonly as the whitetail and the Virginia deer, is a medium-sized species of deer native to North America, North, Central America, Central and South America. It is the ...
in forests and plains where long range, flat shots are necessary. The .300 WSM is also used in
benchrest shooting
Benchrest shooting is a shooting sport discipline in which high-precision rifles are rested on a table or benchrather than being carried in the shooter's handswhile shooting at paper or steel targets, hence the name "benchrest". Both the fo ...
, in 2021 a .300 WSM was used to break the world record for best 10-shot grouping at 1,000 yards at a benchrest competition in Texas.
The .300 WSM has a standard bullet diameter of .308 in (7.62 mm) and takes advantage of the numerous bullet options available in that caliber.
Warnings
The 300 WSM is a
Delta L problem
Delta commonly refers to:
* Delta (letter) (Δ or δ), the fourth letter of the Greek alphabet
* D (NATO phonetic alphabet: "Delta"), the fourth letter in the Latin alphabet
* River delta, at a river mouth
* Delta Air Lines, a major US carrier
...
cartridge, meaning it can present unexpected chambering and/or feeding problems. The
Delta L problem
Delta commonly refers to:
* Delta (letter) (Δ or δ), the fourth letter of the Greek alphabet
* D (NATO phonetic alphabet: "Delta"), the fourth letter in the Latin alphabet
* River delta, at a river mouth
* Delta Air Lines, a major US carrier
...
* 165 gr (10.69 g) Full Metal Jacket (FMJ): 3,223 ft/s (982 m/s)
* 180 gr (11.66 g) Full Metal Jacket (FMJ): 3,095 ft/s (943 m/s)
** Muzzle velocity varies slightly between individual loads and bullet types.
Comparison
Legacy
Of all the short magnums that came out in the 2000's decade the .300 WSM, along with the .270 WSM, are one of the few that have stood the test of time and still have rifles being made for them as of 2025. Both Remington and
Ruger
Sturm, Ruger & Company, Inc., better known by the shortened name Ruger, is an American firearm manufacturing company based in Southport, Connecticut, with production facilities also in Newport, New Hampshire; Mayodan, North Carolina; and ...
no longer manufacture rifles chambered for their proprietary Remington Short Action Ultra Magnum and Ruger Compact Magnum cartridges, although ammunition is still available for them albeit with a limited selection. Among Winchester's short magnums, rifles chambered for the 7mm WSM are no longer made, and the .325 WSM has a limited current production from Winchester. However both the .270 WSM and .300 WSM can be found in a variety of models from major firearms manufacturers including: Remington's Model 700 CDL SF, SPS & SPS Stainless;
Savage
Savage may refer to:
* Savage (pejorative term), a derogatory term to describe a member of a people the speaker regards as primitive and uncivilized
Arts and entertainment Fictional characters
* Bill Savage, in the 2000 AD ''Invasion!'' ...
's Model 110 Apex Hunter, Apex Storm, Long Range Hunter, & High Country; and Winchester's Model 70 Classic Featherweight, Extreme Timber, Extreme Tungsten, Extreme Weather, Long Range & Super Grade; all of which are still chambered for the .270 WSM and .300 WSM.
Winchester Short Magnum
Winchester Short Magnum, or WSM, refers to a family of Rim (firearms), rebated bottlenecked centerfire short magnum Cartridge (firearms), cartridges developed in the early 2000s by the U.S. Repeating Arms Company, the maker of Winchester rifles an ...
*
List of firearms
This is an extensive list of small arms—including pistols, revolvers, submachine guns, shotguns, battle rifles, assault rifles, sniper rifles, machine guns, personal defense weapons, carbines, designated marksman rifles, multiple-barrel firearms ...
*
List of rifle cartridges
List of rifle cartridges, by primer type, Caliber, calibre and name.
File:Cartridge Sample 2.jpg, 350px, From left to right: 1 .17 Hornady Mach 2, 2 .17 Hornady Magnum Rimfire, 3 .22 Long Rifle, 4 .22 Winchester Magnum Rimfire, 5 .17/23 SMc, 6 5mm ...
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Table of handgun and rifle cartridges
This is a table of selected pistol/submachine gun and rifle/machine gun cartridges by common name. Data values are the highest found for the cartridge, and might not occur in the same load (e.g. the highest muzzle energy might not be in the same ...
7 mm caliber
This is a list of firearm cartridges which have bullets in the caliber
In guns, particularly firearms, but not #As a measurement of length, artillery, where a different definition may apply, caliber (or calibre; sometimes abbreviated a ...
*
Delta L problem
Delta commonly refers to:
* Delta (letter) (Δ or δ), the fourth letter of the Greek alphabet
* D (NATO phonetic alphabet: "Delta"), the fourth letter in the Latin alphabet
* River delta, at a river mouth
* Delta Air Lines, a major US carrier
...