300 WSM vs 300 Win Mag: The 30-Caliber Magnum Clash
BY PGF
2 years ago
What Is the Difference Between 300 WSM and 300 Win Mag?
The 300 Winchester Magnum has been around since the 1960’s and has been a favorite for military snipers, big game hunters, and benchrest shooters alike. It is truly in contention for the title of America’s Favorite Magnum Cartridge and is the gold standard by which all belted magnum cartridges are measured.
The 300 Winchester Short Magnum (WSM) is a relative newcomer to the shooting community being released in 2001. The 300 WSM embodies the ballistic advantages of the 300 Win Mag and crams them into a short action rifle.
The result is a lighter rifle with identical barrel length and extremely similar external ballistics. Having a shorter, more maneuverable rifle can be extremely handy when elk hunting in thick brush.
Both rifle cartridges are extremely accurate and can easily achieve MOA to sub-MOA level accuracy with match grade factory loads or properly tuned handloads.
Although both cartridges are excellent for hunting or target shooting, they are not without their disadvantages.
Some detractors of the 300 WSM will point to its rebated rim, claiming that this might inhibit the ability of the bolt to push the cartridge from the magazine into the chamber. The 300 WSM’s steep 35-degree shoulders also play a part in this critique, as some forum users theorize that the sharp angle might hinder smooth feeding into the chamber.
Although I will say that feeding a 300 WSM is not as smooth as the experience with other cartridges, I’ve yet to experience a jam.
For the 300 Winchester Magnum, most of the complaints center around the useless belt on the cartridge case. As you’ll learn later in the history of the 300 Win Mag, the belted case is an artifact from the parent 375 H&H Magnum case.
Early rifles used the belt for headspacing, which caused premature case stretching and thereby reduced the lifespan of the brass. If all you shoot is factory ammo and you aren’t into reloading, this is a non-issue. However, for handloaders it’s a serious problem as it means you will have to replace your 300 Win Mag brass more frequently.
Many 300 Win Mag rifles now have their chambers reamed to headspace off the case shoulders, which eliminates premature case stretching entirely.
The last strike against the 300 Win Mag is the painfully short case neck. Some long range target shooting gurus state that the 300 Win Mag’s neck is not long enough to securely hold the projectiles and maintain concentricity. In theory, this could cause the bullet to enter the rifling off-axis and affect point of impact for long distance shots.
However, based on the lack of complaints by military snipers who routinely shoot well past 1000 yards with a 300 Win Mag, I’m guessing this critique is more an online forum talking point as opposed to a real-world issue.
In the following sections, we will analyze the 300 WSM vs 300 Win Mag in detail so you can understand the differences between these two rifle cartridges.
The article discusses Sectional Density, Ballistic Coefficient, Trajectory, Reloading, Ballistics, and other aspects.
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On October 25, 2022 at 9:31 pm, Georgiaboy61 said:
Re: “The last strike against the 300 Win Mag is the painfully short case neck. Some long range target shooting gurus state that the 300 Win Mag’s neck is not long enough to securely hold the projectiles and maintain concentricity.
The whole point of 300 Win-Mag was to duplicate 300 H&H ballistics and performance from a standard long-action rather than a magnum-length action such as that used by the British design. The shorter-than-caliber neck is one concession made by the designers to fit the case into a long-action.
The various short magnums all have impressive things they do well, but why abandon decades of information and rifle dope on the 300WM? A cartridge which has been used for everything from elk hunters to police and military snipers to competitors shooting the 1,000 yard stage of long-range contests.
The standard knock on the 300WM is that its OAL is too-short to allow long-for-caliber projectiles to be loaded internally in the magazine. This is sometimes a drawback, but at other times not. Shooting long-range stages in competition is often slow-fire prone, so loading singly isn’t necessarily a detriment.
The other consideration for some users is that standard 300WM barrels used for hunting rifles tend to be 1:10 RHT and may not be quite fast-enough to handle bullets heavier than 220-grains, or some of the longer 230-250-grain loads.
These considerations may account for the rise in popularity of such cartridges as 300 PRC, 300 Norma Magnum, and the like. Rapid advances in bullet design over the last twenty-five years or so have also propelled a lot of new interest in .30-caliber chamberings, especially the new very high-B.C. 225-250-grain loads which push the envelope of thirty caliber cartridges firmly into .338-caliber territory.
On October 26, 2022 at 3:13 pm, Old Bill in TN said:
As for the case neck critique, the Seals utilize the 300WM on man size targets out to 1500 meters. That pretty well puts the criticism to rest in my book.
On October 26, 2022 at 11:14 pm, Georgiaboy61 said:
@ Old Bill in TN
Re: “As for the case neck critique, the Seals utilize the 300WM on man size targets out to 1500 meters. That pretty well puts the criticism to rest in my book.”
Yes, that’s right. Navy SEAL Chief Petty Officer Chris Kyle, the top-scoring sniper in U.S. military history, used a heavily-modified Remington M700 in 300 Win-Mag as his go-to rig when in action in Iraq. As is related in his life story, his rig for extreme long-range shots was either a Barrett 50-cal or a rifle in 338 Lapua Magnum, but he relied on the 300WM a lot for day-to-day use, alongside his weapons in 7.72×51 NATO.
Elk hunters have done very well indeed with the cartridge over the years, such that some years back Winchester put out a commemorative “Rocky Mountain Elk Foundation” edition of their Model 70 bolt-action rifle.
Why fix what isn’t broken?