300 Win Mag vs 300 WSM – Updated 2022 Comparison

The comparison of the .300 Winchester Magnum and .300 Winchester Magnum rounds is a peculiar story in the firearms world. The latter seems to be a smaller version of the former round and people say that there should be a considerable difference in this performance. The smaller size of the .300 WSM does indicate so, but is that the case always?

Here is a detailed guide to the comparison of these rounds and you will be amazed to find the similarities and differences between these two. 

TL;DR: 300 Win Mag vs 300 WSM

Take a quick peek on the pros and cons of these rounds.

300 Win Mag Overview

The .300 Winchester Magnum, also known as .300 Win Mag or .300 WM is a bottlenecked, belted, magnum rifle cartridge that fires a .308 inch diameter bullet. It was designed using the .375 H&H as the parent case, reducing its taper and shortening the neck to accept a smaller  .308 inch diameter bullet.

The predecessor of this round was the .338 Winchester Magnum introduced in 1958. It was slightly lengthened and the shoulder was moved a bit forward.

This round was introduced by Winchester in 1963 after experimenting with a few other magnum cartridges before. It comes from a family of cartridges that can be fired from a standard/long action rifle and do not need a magnum chamber. A few other cartridges, like the .300 H&H Magnum which were similar in design, were introduced before the .300 WM on the market.

However, eventually, the .300 WM still survives and is extremely popular for big game hunting and long range competitions. It is a very flat shooting cartridge and renowned for its power.

300 WSM Overview

The .300 Winchester Short Magnum, also known as the .300 WSM is a rimless, bottlenecked, centerfire rifle cartridge introduced by Winchester on the market in 2001. It can be seen as a shortened version of the .300 Win Mag with lesser powder and a shorter overall length.

The amazing advantage of the .300 WSM is that it delivers almost the same performance as the longer .300 WM cartridges in a shorter case. It eliminated the belted case and head-spaces off of the case shoulder 

The purpose of developing a short magnum cartridge is to condense the gunpowder in a more compact space close to the primer’s flash hole. Thus delivering uniform ignition of the propellant and slightly adding to the velocity. 

The .300 WSM uses a rebated rim design, using a rim diameter almost the same as the .300 Win Mag. It is comparable in overall length to a .308 Winchester and fits a short action, making cycling quicker.

300 Win Mag vs 300 WSM: Cartridge Specs

Here’s a quick side-by-side comparison of the .300 Win Mag and the .300 WSM cartridges. 

	300 Win Mag	300 WSM
Bullet Diameter	.308 in (7.8 mm)	.308 in (7.8 mm)
Neck Diameter	.339 in (8.6 mm)	.344 in (8.7 mm)
Base Diameter	.513 in (13.0 mm)	.555 in (14.1 mm)
Case Length	2.62 in (67 mm)	2.100 in (53.3 mm)
Overall Length	3.34 in (85 mm)	2.860 in (72.6 mm)
Case Capacity	93.8 grains	80.4 grains
Max Pressure (SAAMI)	64,000 psi	63,817 psi
Typical Casing Material	Brass	Brass
Typical Bullet Weight (gr)	160-220 grains	150-200 grains

As you can already see, the .300 WSM is just a shortened version of the .300 WM, but in a slightly different manner. The whole point of developing the .300 WSM was to create a shorter version without compromising on performance. Indeed Winchester has fared very well on that promise.

The shortening in the length of the .300 WSM brings it down to a short action cartridge length. Interestingly, the .300 WM is already an innovatively designed round that fits standard actions and does not need a magnum length action. 

The .300 WSM has a 20% lesser case capacity, but it comes loaded at almost the same chamber pressure as the .300 WM. The .300 WM is comparable to a .30-06 in size, whereas the .300 WSM is equal to a .308 Win. 

Talking about the weight of the bullets, both these cartridges handle almost the same weight of bullets. However, the .300 WM has a higher ceiling for maximum weight and goes beyond 200 grains and up to 300 grains. 

While the .300 WSM has a larger base diameter, it uses a rebated rim to fit the bolt head. However, this does not make these cartridges or rifle parts interchangeable by any means.

300 Win Mag vs 300 WSM: Ballistics

The study of ballistics deals with understanding the behavior of a moving projectile at varying distances. This helps us understand if a bullet will be suitable for short, medium, or long range, or perhaps if the bullet is suitable for any specific application. There are three major factors under ballistics, trajectory, velocity, and kinetic energy. 

300 Win Mag vs 300 WSM: Trajectory

Here’s a quick table defining how these rounds perform at short and long ranges.

300 Win Mag

24” barrel/BC 0.398/165 grains Barnes Triple-Shock X Bullet	24” barrel/BC 0.507/180 grains Nosler Accubond	24” barrel/BC 0.608/200 grains Edge TLR
200 yds: 2.9 “ Drop	200 yds: 3 “ Drop	200 yds: 3.4 “ Drop
300 yds: 11 “ Drop	300 yds: 11.2 “ Drop	300 yds: 12.3 “ Drop
400 yds: 25.5 “ Drop	400 yds: 25.3 “ Drop	400 yds: 27.4 “ Drop
500 yds: 47.3 “ Drop	500 yds: 46.3 “ Drop	500 yds: 49.6 “ Drop
1,000 yds: 344.2 “ Drop	1,000 yds: 300.3 “ Drop	1,000 yds: 301.8 “ Drop

 

300 WSM

24” barrel/BC 0.398/165 grains Barnes Triple-Shock X Bullet	24” barrel/BC 0.507/180 grains Nosler Accubond	24” barrel/BC 0.608/200 grains Edge TLR
200 yds: 2.7 “ Drop	200 yds: 3 “ Drop	200 yds: 3.4 “ Drop
300 yds: 10.3 “ Drop	300 yds: 11.2 “ Drop	300 yds: 12.3 “ Drop
400 yds: 23.9 “ Drop	400 yds: 25.3 “ Drop	400 yds: 27.4 “ Drop
500 yds: 44.4 “ Drop	500 yds: 46.3 “ Drop	500 yds: 49.6 “ Drop
1,000 yds: 323.1 “ Drop	1,000 yds: 300.3 “ Drop	1,000 yds: 301.8 “ Drop

The comparison of trajectories for both these rounds is pretty much straight. Except for the 165-grain variants, the other two bullet types show the same trajectory out to 1,000 yards. I used the same bullets to get an exact idea of how these rounds are going to perform.

It is true that different bullets will perform differently, and if you combine the average of the rounds available for these two cartridges. The .300 WSM seems to have a little edge over the .300 Win Mag but only by a few inches or so on long range.

The fact that there are many different rounds and each of them performs differently. It will not be fair to give either of these an edge over the other, at least when the trajectory is concerned. Both these rounds were designed for long range engagements, and they certainly do that with great accuracy.

300 Win Mag vs 300 WSM: Velocity & Kinetic Energy

Here are the velocity and kinetic energy values of both these rounds for a quick overview.

300 Win Mag

24” barrel/BC 0.398/165 grains Barnes Triple-Shock X Bullet	24” barrel/BC 0.507/180 grains Nosler Accubond	24” barrel/BC 0.608/200 grains Edge TLR
100 yds: 2,810 ft/s, 2,892 ft.lbs	100 yds: 2,774 ft/s, 3,075 ft.lbs	100 yds: 2,660 ft/s, 3,141 ft.lbs
200 yds: 2,582 ft/s, 2,442 ft.lbs	200 yds: 2,595 ft/s, 2,692 ft.lbs	200 yds: 2,514 ft/s, 2,806 ft.lbs
300 yds: 2,365 ft/s, 2,049 ft.lbs	300 yds: 2,424 ft/s, 2,348 ft.lbs	300 yds: 2,373 ft/s, 2,500 ft.lbs
400 yds: 2,159 ft/s, 1,707 ft.lbs	400 yds: 2,259 ft/s, 2,039 ft.lbs	400 yds: 2,236 ft/s, 2,221 ft.lbs
500 yds: 1,963 ft/s, 1,411 ft.lbs	500 yds: 2,100 ft/s, 1,763 ft.lbs	500 yds: 2,105 ft/s, 1,967 ft.lbs
1,000 yds: 1,197 ft/s, 525 ft.lbs	1,000 yds: 1,419 ft/s, 805 ft.lbs	1,000 yds: 1,520 ft/s, 1,026 ft.lbs

300 WSM

24” barrel/BC 0.398/165 grains Barnes Triple-Shock X Bullet	24” barrel/BC 0.507/180 grains Nosler Accubond	24” barrel/BC 0.608/200 grains Edge TLR
100 yds: 2,885 ft/s, 3,049 ft.lbs	100 yds: 2,774 ft/s, 3,075 ft.lbs	100 yds: 2,660 ft/s, 3,141 ft.lbs
200 yds: 2,653 ft/s, 2,589 ft.lbs	200 yds: 2,595 ft/s, 2,692 ft.lbs	200 yds: 2,514 ft/s, 2,806 ft.lbs
300 yds: 2,433 ft/s, 2,169 ft.lbs	300 yds: 2,424 ft/s, 2,348 ft.lbs	300 yds: 2,373 ft/s, 2,500 ft.lbs
400 yds: 2,224 ft/s, 1,811 ft.lbs	400 yds: 2,259 ft/s, 2,039 ft.lbs	400 yds: 2,236 ft/s, 2,221 ft.lbs
500 yds: 2,024 ft/s, 1,501 ft.lbs	500 yds: 2,100 ft/s, 1,763 ft.lbs	500 yds: 2,105 ft/s, 1,967 ft.lbs
1,000 yds: 1,232 ft/s, 556 ft.lbs	1,000 yds: 1,419 ft/s, 805 ft.lbs	1,000 yds: 1,520 ft/s, 1,026 ft.lbs

Again, the speed characteristics for both these rounds are almost the same. At varying ranges, the velocity values for different rounds may differ. However, this difference is really low and does not cross 100 fps, no matter which round you choose. 

In some cases, especially with the lightweight loads, the .300 WSM has a slight advantage in velocity. This can be seen as a result of the compactly condensed powder that burns uniformly without wasting a grain. 

Both these rounds stay supersonic beyond 1,000 yards, and in fact, this range extends out to 1,300 yards on average. So both these rounds are great for long range applications and can be predicted for accuracy. 

Now moving on to the energy characteristics, again, the difference is negligible. The slightly more velocity of either of these rounds will not create a big difference in the delivery of power. Additionally, as the bullets being used are the same, and also being propelled at similar velocities. It is naive to expect that one is better than the other. Both of these retain enough energy to bring down an elk at 500 yards. 

300 Win Mag vs 300 WSM: Stopping Power

The stopping power of a bullet defines how quickly it can obliterate a target. For example, if the purpose is to hunt a game animal. The stopping power will help you understand how much damage does the bullet cause and if more than one shot is needed at a specific range for a particular animal. 

300 Win Mag vs 300 WSM: Momentum & Sectional Density

Here is the sectional density and momentum data for both these rounds. 

300 Win Mag

 

24” barrel/BC 0.398/165 grains Barnes Triple-Shock X Bullet Sectional Density: 0.248	24” barrel/BC 0.507/180 grains Nosler Accubond Sectional Density: 0.271	24” barrel/BC 0.608/200 grains Edge TLR Sectional Density: 0.301
100 yds: 66 lb.ft-s	100 yds: 71 lb.ft-s	100 yds: 76 lb.ft-s
200 yds: 61 lb.ft-s	200 yds: 66 lb.ft-s	200 yds: 71 lb.ft-s
300 yds: 55 lb.ft-s	300 yds: 62 lb.ft-s	300 yds: 67 lb.ft-s
400 yds: 50 lb.ft-s	400 yds: 58 lb.ft-s	400 yds: 63 lb.ft-s
500 yds: 46 lb.ft-s	500 yds: 54 lb.ft-s	500 yds: 60 lb.ft-s
1,000 yds: 28 lb.ft-s	1,000 yds: 36 lb.ft-s	1,000 yds: 43 lb.ft-s

 

300 WSM

 

24” barrel/BC 0.398/165 grains Barnes Triple-Shock X Bullet Sectional Density: 0.248	24” barrel/BC 0.507/180 grains Nosler Accubond Sectional Density: 0.271	24” barrel/BC 0.608/200 grains Edge TLR Sectional Density: 0.301
100 yds: 68 lb.ft-s	100 yds: 71 lb.ft-s	100 yds: 76 lb.ft-s
200 yds: 62 lb.ft-s	200 yds: 66 lb.ft-s	200 yds: 71 lb.ft-s
300 yds: 57 lb.ft-s	300 yds: 62 lb.ft-s	300 yds: 67 lb.ft-s
400 yds: 52 lb.ft-s	400 yds: 58 lb.ft-s	400 yds: 63 lb.ft-s
500 yds: 47 lb.ft-s	500 yds: 54 lb.ft-s	500 yds: 60 lb.ft-s
1,000 yds: 29 lb.ft-s	1,000 yds: 36 lb.ft-s	1,000 yds: 43 lb.ft-s

 

The two most definitive values to calculate the stopping power of a bullet are momentum and sectional density (SD). The momentum of an object is the measure of the level of energy transfer it can cause when moving. This directly concerns the size of the wound cavity. 

The sectional density is the ratio between the mass and cross-sectional area of a bullet. The higher the value of SD, the more penetration will be delivered by a bullet. An SD of 0.230 to 0.270 is considered good for a deer-sized game, and an SD of 0.270 to 0.300 is good for big game. Anything more is good for a dangerous big thick-skinned game. 

As the table above mentions, the SD for these rounds is always above 0.240. Heavier bullets have higher SD’s and the heaviest bullets have an SD of more than 0.300. So either of these rounds is good for big and dangerous big games. 

As far as momentum is concerned, it is the product of the mass and velocity of a moving object. Since the difference in velocity for comparable bullet weights is negligible, the momentum values are almost always the same. In layman terms, your target will not notice the difference.

300 Win Mag vs 300 WSM: Use Cases & Effective Range

Now let’s quickly understand how each of these rounds will perform for different applications.

Long Range Uses

 Either of these rounds is perfect for long range engagements. It all depends upon the choice of ammunition. The ballistic coefficient for some rounds can go as high as 0.600, and the average value of all the available options is around 0.483. So these rounds will fare up very well against the drift. 

Additionally, the flatter trajectory of these rounds needs very little room for adjustment in the long range. The effective point-blank range for both these rounds is significantly high and you can rely upon it for accuracy. In fact, many pro shooters use the .300 WM for long range F-class competitions. 

Medium or Short Range Use

Each of these rounds is very suitable for medium ranges, i.e, a distance of up to 500 yards. The trajectory is very flat and the BC’s are high. If you do not mind the extra recoil and want to bring these rounds for medium range, it is completely your choice.

Talking about short range, the .300 WSM can fit a short action, which makes it technically suitable for a sporting or tactical rifle like the AR-15. The recoil is close to 25 foot pounds, which is just a couple of pounds lesser than the .300 WM. There are a ton of more controllable options out there, so the short range is an absolute no-go. 

Hunting

On a general note, either of these rounds is 100% reliable for hunting any critter that roams this planet. From deer to grizzly bears and even big north African plain game, there is nothing these rounds cannot handle. 

These rounds are widely recommended for hunting big game because of their immense power and also the flat trajectory. So even if you are at a significant distance from your quarry, you can make a definite hit. 

If you do not mind the extra weight of the rifle and a slightly extra recoil, I think these rounds will make up for a great mountain hunting rifle. Additionally, I think it is better to pull these cartridges out when you are exclusively hunting big game. That’s because there are certainly a lot of other more controllable options for hunting deer-sized game. 

300 Win Mag vs 300 WSM: Costs, Availability, & Compatibility

The .300 WM and .300 WSM have been around for a while, and if you plan on using them, it is important to understand the rifle options and the scope for customizability. 

Pricey But Available

I suggest you also look for a good handloading setup for both these cartridges. 

Good vs Little Options

While the availability of rifle options for the .300 WM is huge, the .300 WSM has very few rifle options available on the market. Additionally, rifles are mostly limited to bolt action for the .300 WM, with only a couple of options in semi-auto. The availability of parts and ammo for the .300 WSM is scarce in comparison to the .300 WM. 

Bottom Line

The .300 Winchester Short Magnum is a shortened version of the .300 Winchester Magnum cartridge. Even with its shorter length and lesser powder, the .300 WSM delivers performance almost the same as the .300 WM. So what is the difference? 

If you are looking for a shorter and lighter rifle chambered with a standard action magnum cartridge, you can choose .300 WSM over the .300 WM. Additionally, the short OAL of the .300 WSM will also help with quicker cycling and lesser movement. Other than that, both these rounds are just the same.