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The 300 Winchester Magnum (300 Win Mag) and 308 Winchester (308 Win) are the two most successful 30-caliber big game hunting and long-distance shooting rifle cartridges in the world. Although they both shoot the same diameter bullets, the 300 Win Mag and the 308 Winchester each have their distinct advantages when it comes to cartridge selection.

We're going to take a detailed look at the history, ballistics, and performance of these two long-range rifle cartridges so you can make a more informed decision on which precision or hunting rifle you will add to your gun safe next.

Get out your bullet drop charts and your spotting scope, because we are talking long-range shooting today with the two most popular 30-caliber rifle cartridges in North America!

The History of 300 Win Mag and 308

300 Win Mag – Joining the Magnum Lineage – “Do you feel lucky, punk?!”

Let’s call a spade a spade my fellow shooters, here in North America we like our Magnum cartridges! From Elmer Keith, Bill Jordan, and Dirty Harry with his .44 Magnum Smith and Wesson handgun to big game hunters in the forests of Northern Canada, many shooters like that extra stopping power that magnum cartridges bring to the table.

The 300 Winchester Magnum steps into the Magnum Lineage like any other magnum cartridge on the market…with a deafening BANG!

Before the 300 Winchester Magnum exploded onto the shooting scene in 1963, there were several other 30-caliber options that we would classify as Magnum ammo by today’s standards. The most prominent of these was the 300 H&H Magnum that had been on the market since 1925. However, the 300 H&H Magnum could not fit into a standard action Mauser or Springfield receiver and required a custom Magnum action, which severely handicapped its acceptance in the shooting community.

The next attempt at a magnum rifle cartridge was by Roy Weatherby with the 270 Weatherby Magnum in 1943 and the 300 Weatherby Magnum in 1944.

300 Win Mag: Genesis of the Quintessential Big Game Hunting Cartridge

In 1958, Winchester figured they should probably get in on the magnum craze and introduced 3 new cartridges to their line: the 264 Winchester Magnum, the 338 Winchester Magnum, and the 458 Winchester Magnum.

Notice any glaring omission from that list? There’s no 30-caliber option!

Wildcatters (hand loaders who take it upon themselves to develop new cartridges) quickly jumped on this glaring hole in the Winchester line and developed the 30-338 Winchester. Norma Precision also took the opportunity to get in on the action and developed the 308 Norma Magnum in 1960.

It was at this point that Winchester figured that they might do well by introducing a 30-caliber magnum rifle cartridge offering. In 1963, Winchester introduced the 300 Win Mag in its long-action Model 70 bolt action rifle.

Quickly following suit, Remington introduced a 300 Win Mag offering in its popular Rem 700 bolt action rife. Since then, the 300 Winchester Magnum has quickly become one of the most successful magnum rifle cartridges on the market today.

The 300 Winchester Magnum was developed from the belted 375 H&H Magnum cartridge and sports a whopping case capacity of 91.5 gr of water and a max pressure of 64,000 psi based on SAAMI specifications. This voluminous case capacity allows the 300 Win Mag to pack in the powder and push the .308” diameter bullet to its limits.

At the muzzle, a 150 grain bullet is screaming downrange at about 3300 fps with a back-breaking 3600 ft lbs of energy. That's some serious power!

Many shooters believe that the belt around the case head is required to contain the “case-splitting” pressure that the 300 Win Mag must exude. However, this is a common misconception. Based on the case design, the belted cartridge is superfluous. However, Winchester retained the design as a marketing strategy to link the cartridge to its heavy-hitting predecessor.

308 Winchester: A Military Classic and Civilian Staple

The development of the 308 Winchester (military designation - 7.62x51mm NATO) began after the Korean War to replace the long-serving 30-06 Springfield round. In 1958, the military officially adopted the 7.62x51mm NATO as their new cartridge and it saw limited service in Vietnam before being replaced by the 5.56x45mm NATO (223 Remington).

Winchester quickly saw the utility of the 7.62x51mm NATO round on the civilian market and introduced the new rifle cartridge as the 308 Winchester in its short-action Model 70 rifle. The 308 Winchester quickly became one of the most popular long-distance target shooting and hunting rounds and can easily harvest small to medium size game animals.

I went into a detailed description of the history of the 308 Winchester in this article if you’d like to know more: 308 Win vs 6.5 Creedmoor – A Battle of Ballistic Coefficients

300 Win Mag vs 308: The Showdown

Now that you’ve gotten a better understanding of the history behind these two iconic rifle cartridges from Winchester, it’s time to compare the two and discover their strengths and weaknesses for your intended purpose.

Cartridge Dimensions

When comparing the 300 Win Mag to the 308 Win, it’s difficult to ignore the sheer overall length difference between the two cartridges.

To put it mildly, the 300 Win Mag simply dwarfs the 308 Winchester by almost half an inch when looking at overall length. Furthermore, the 300 Win Mag has almost 60% more case capacity than its smaller counterpart.

This massive case length difference comes at some cost to the 300 Win Mag. First off, rifles will generally be larger and heavier. That might not sound like a big deal, but when you’re humping a 9-pound rifle through the Alaskan bush, it can wear you down quickly. Furthermore, 300 Win Mag ammo will be heavier than 308 by a large margin.

When it comes to backpacking, the old saying goes, “ounces equal pounds,” and this is something to consider when you're selecting a cartridge for your next hunting rifle.

If you’re planning on doing long-range shooting, then the weight difference becomes irrelevant and can actually be a benefit as the rifle will absorb some of the recoil.

Recoil

This is where these two rifle cartridges really separate themselves. These cartridges generate significant recoil compared to lighter rounds like the 6.5 Creedmoor and the 223 Remington. Furthermore, felt recoil can differ between different rifles and bullet weights.

That being said, 300 Win Mag recoil is very stout (read – shoulder bruising) and there is a noticeable difference between the two rifle cartridges. The numbers don’t lie as the 308 has about 40-50% less felt recoil when compared to the 300 Win Mag.

Now you might be thinking to yourself, “Just man up and take it! Chris told me that all this fancy-schmancy ballistic data for the 300 Win Mag was worth it!”

In many circumstances, you might be right. However, recoil is a factor that can greatly affect accuracy for newer shooters – shoulder fatigue is real and should not be ignored.

After firing off a few 300 Win Mag rounds and having that rifle pound your shoulder, it’s not atypical to start developing a flinch and sending your rounds off target. This can affect your shot placement and mean the difference between cleanly harvesting a big game animal or simply wounding it.

For a newer shooter/hunter, there’s no question that the 308 Winchester is going to be the better option for the majority of your needs. You’ll be able to practice longer without developing bad shooting habits.

Velocity

The first piece of ballistic data that most shooters look at is velocity. This is simply how fast the bullet is moving at a given range measured in fps (feet per second). When looking at velocity, it’s important to look at how fast the round hemorrhages speed at a distance because this will impact how long the bullet will remain supersonic (above the speed of sound). Once a bullet drops into subsonic speeds, it loses a lot of predictability and can be affected by wind and gravity considerably more.

Looking at the ballistics tables, we see that the 300 Winchester Magnum can send a 180 grain bullet (which is a heavy-hitting hunting round) at a muzzle velocity near 3000 fps, while the 308 Win can muster up about 2600 fps. That 400 fps difference is significant when shooting out past 500 yards.

When engaging a target out past 500 yards, the 300 Win Mag will retain more of its velocity and remain supersonic for longer, this makes it the better choice for shots at longer ranges.

Trajectory

The trajectory is the measure of a bullet’s path in its flight to the target. Internet forums, Hollywood, and sensational advertisements from manufacturers might make you think that their new cartridge shoots in a straight line – that simply is not true.

Gravity is going to affect a bullet in flight the longer it remains above the dirt. The old adage holds true, “What goes up must come down.” No matter how fast a bullet flies, eventually, gravity is going to pull it back to earth.

That being said, we can look at bullet drop numbers at range and determine which cartridge has a flatter trajectory. In the case of 300 Win Mag vs 308, there is simply no contest. 300 Win Mag clearly has a flatter trajectory similar to that of the 6.5 Creedmoor. A flat trajectory is ideal because it allows for a little more forgiveness when it comes to calculating bullet drop at range. Shot placement is always the key to ethically harvesting a game animal no matter what cartridge you choose.

However, the 300 Win Mag will have a flatter trajectory overall. Looking at our 180 grain bullet on the ballistics chart, we see that the bullet fired from the 308 will drop approximately 10” more than the same bullet fired from a 300 Win Mag. That’s almost a full foot and the numbers only get bigger the farther out you go! This means that the 300 Win Mag will allow you to shoot longer ranges with fewer adjustments in your scope.

Max Range

The maximum effective range of a bullet can depend greatly on loading and environmental conditions. However, the typical convention for defining maximum range is the range at which the bullet goes subsonic. The 300 Win Mag, with its increased case capacity and higher average velocity, can maintain supersonic flight out to an average of 1200 yards, while the lower recoil 308 Winchester will begin to fall below the sound barrier near 1000 yards.

The increased muzzle velocity really pays dividends when you are looking to shoot long distance and the 300 Win Mag gets the nod for overall maximum range.

Ballistics Coefficient

A ballistic coefficient (BC) is a number that many shooters will run across when doing cartridge research but often have no idea what it means. To put it in layman’s terms, the ballistic coefficient is a numerical representation of how aerodynamic and streamlined a bullet is. The higher the number, the less the bullet will be affected by wind drift and air resistance.

This translates to the higher the number, the fewer scope adjustments you’ll need to make for proper shot placement. When it comes to the ballistic coefficient between the 308 and the 300 Win Mag, both offer amazing BC offerings over 0.4, which is very solid.

That being said, the average BC for 308 Winchester is around 0.43 and 0.49 for 300 Win Mag. This should not be overly surprising given the other factors that we’ve discussed so far.

Sectional Density

Sectional density is another “nickel word” that is often found when researching your next hunting rifle. Simply put, it’s a measure of a given bullet’s ability to penetrate a target. Sectional density is mathematically derived by comparing the bullet weight to its diameter. Since the 300 Win Mag and the 308 both shoot the same diameter bullet, the major defining factor will be the bullet weight.

With its increased case capacity, the 300 Win Mag can accept heavier bullets than its lightweight counterpart, the 308 Winchester. Therefore, a 300 Win Mag will offer a higher sectional density (on average) than 308 Win.

Stopping Power

Stopping power is a term that’s thrown around on internet forums with reckless abandon at times, with users making broad statements that one round has more stopping power than another. Often this comes up more frequently with handgun calibers like 9mm verses 40S&W verses 45ACP.

I want to make this point extremely clear, the 308 and the 300 Win Mag both have incredible stopping power and can easily harvest whitetail deer and elk at average hunting ranges (within 300 yards). The consensus in the hunting community is that a bullet can ethically harvest a whitetail deer with 1000 ft lbs of energy and an elk with 1400 ft lbs of energy.

For your large game animals like bears, elk, and moose, the 308 can do the job out to about 350 yards while the 300 Win Mag can maintain this level of knockdown power out to 600 yards. The 308 has enough stopping power to drop a whitetail out to about 500 yards while the 300 Win Mag is pushing 800 yards for this shot.

Bottom line – the 300 Win Mag can maintain enough energy and velocity at longer ranges to ethically harvest big game animals.

Accuracy

Both the 300 Win Mag and the 308 have superb accuracy and can easily shoot sub-MOA groups (1 inch at 100 yards). That being said, I’m going to have to give 308 the edge in accuracy here due to one important factor – recoil.

With lower recoil, there is less potential for shooters to flinch when squeezing the trigger–less recoil anticipation and flinch will translate to better downrange results. This is not to say that the 300 Win Mag is inaccurate. On the contrary, it is and is winning 1000-yard shooting competitions left, right, and center so it is more than accurate enough. Most shooters will tell you that they “just shoot better with their 308,” and the lower recoil is why.

Price and Availability

The 308 lends itself to be considerably more affordable than its magnum counterpart as the round is simply smaller. With a smaller size comes less powder and less brass needed for the cartridge case. Before the 2020 ammo shortage (aka “the good old days”), you could pick up reasonably priced 308 for $15/box while match-grade ammo would run you about $50/box. Compare that to 300 Win Mag where the cheap ammo will start around $25/box and the premium ammo will be over $65/box.

Barrel Life

All of that increased case capacity and powder charge comes at a price for the 300 Win Mag. The larger powder charge will introduce more wear and tear on a barrel, and it is not uncommon for a 308 barrel to last 2-3x longer than a 300 Win Mag barrel.

For your average hunter, barrel life will rarely come into account as they are not putting enough rounds downrange for this to matter. However, for precision shooters who spend a lot of time at the range, this can become a factor.

Bullet Selection

You would think that since both the 308 and the 300 Win Mag fire the same caliber bullets, this category would be a wash. However, with its increased case capacity, the 300 Win Mag can accept heavier loadings than the 308 Winchester.

Heavier bullets will translate to higher ballistic coefficient and sectional density, which are all important for taking long-range shots. The maximum bullet weight that you typically see in 308 is 180 grains, while in 300 Win Mag it is not too difficult to find 220 grain bullet weight offerings. This adds a bit more versatility to bullet selection for the 300 Win Mag.

Ease of Reloading

Reloading, or handloading, is an important thing to consider when selecting a rifle cartridge if you like to “dial-in” the perfect loading for your bolt action rifle. Both the 300 Win Mag and the 308 are a joy to reload with numerous bullet weight options, powders, and primers available to choose from.

The Nosler AccuBond, Hornady GMX, and Barnes TSX also offer amazing expansion to quickly and accurately claim that trophy bull elk on the business end of your rifle.

Continue reading 300 Win Mag vs 308 Caliber Comparison: A Clash of 30-Caliber Titans at Ammo.com.