| 300 Winchester Short Magnum | ||||||||||||||||||||
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| Type | Rifle | |||||||||||||||||||
| Place of origin | United States | |||||||||||||||||||
| Production history | ||||||||||||||||||||
| Designer | Winchester | |||||||||||||||||||
| Designed | 2001 | |||||||||||||||||||
| Manufacturer | Winchester | |||||||||||||||||||
| Produced | 2001–present | |||||||||||||||||||
| Specifications | ||||||||||||||||||||
| Case type | Rebated-rimmed, bottleneck | |||||||||||||||||||
| Bullet diameter | .308 in (7.8 mm) | |||||||||||||||||||
| Land diameter | .300 in (7.6 mm) | |||||||||||||||||||
| Neck diameter | .344 in (8.7 mm) | |||||||||||||||||||
| Shoulder diameter | .538 in (13.7 mm) | |||||||||||||||||||
| Base diameter | .555 in (14.1 mm) | |||||||||||||||||||
| Rim diameter | .535 in (13.6 mm) | |||||||||||||||||||
| Case length | 2.100 in (53.3 mm) | |||||||||||||||||||
| Overall length | 2.860 in (72.6 mm) | |||||||||||||||||||
| Case capacity | 80.4 gr | |||||||||||||||||||
| Rifling twist | 1-10" | |||||||||||||||||||
| Primer type | Large rifle magnum | |||||||||||||||||||
| Maximum pressure (C.I.P.) | 63,817 psi (440.00 MPa) | |||||||||||||||||||
| Ballistic performance | ||||||||||||||||||||
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| Test barrel length: 24" Source(s):Reloading data at Accurate Powder  | ||||||||||||||||||||
300 Winchester Short Magnum (also known as300 WSM) is a .30caliberrebated rim bottleneckedcenterfire shortmagnumcartridge that was introduced in 2001 byWinchester.[1]
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.[2] 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.[3] The .300 WSM has a case capacity of 80 grains.[2] The.30-06 Springfield holds 69 grains;[4].308 Winchester holds 56 grains;[5] .30-30 Winchester holds 45 grains;[6].300 Winchester Magnum has a case capacity of 93.8 grains.[7] 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.[8]
The advantage to this round is the ballistic performance is nearly identical to the.300 Winchester Magnum[9] 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 highbolt thrust 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.[8]
The .300 WSM is adequate for hunting all types ofbig game inNorth America including (but not limited to):moose,black bear,brown bear,elk,black-tailed deer,mule deer, andwhite-tailed deer in forests and plains where long range, flat shots are necessary.[10][11] The .300 WSM is also used inbenchrest shooting, 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.[12][13]
The .300 WSM has a standard bullet diameter of .308 in (7.82 mm) and takes advantage of the numerous bullet options available in that caliber.[14][15]
The 300 WSM is aDelta L problem cartridge, meaning it can present unexpected chambering and/or feeding problems. TheDelta L problem article explains this problem in more detail. The.300 Remington Short Action Ultra Magnum has very similar cartridge dimensions but is not interchangeable.[3]
| Cartridge | Bullet Weight (gr) | Muzzle velocity (fps) | Muzzle energy (Ft-lbs) |
|---|---|---|---|
| 300 WSM | 200 | 2822 | 3536 |
| .300 RSAUM | 200 | 2790 | 3456 |
| .300 Win Mag | 200 | 2850 | 3607 |
| .300 Wby Mag | 200 | 3060 | 4158 |
| .300 RUM | 200 | 3154 | 4417 |
| .30-06 Springfield | 200 | 2569 | 2930 |
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. BothRemington andRuger no longer manufacture rifles chambered for their proprietary Remington Short Action Ultra Magnum andRuger Compact Magnum cartridges, although ammunition is still available for them albeit with a limited selection.[17][18] Among Winchester's short magnums, rifles chambered for the7mm WSM are no longer made, and the.325 WSM has a limited current production from Winchester.[3] However both the .270 WSM and .300 WSM can be found in a variety of models from major firearms manufacturers including: Remington'sModel 700 CDL SF, SPS & SPS Stainless;[19]Savage'sModel 110 Apex Hunter, Apex Storm, Long Range Hunter, & High Country;[20] and Winchester'sModel 70 Classic Featherweight, Extreme Timber, Extreme Tungsten, Extreme Weather, Long Range & Super Grade;[21] all of which are still chambered for the .270 WSM and .300 WSM.
