The .300 Winchester Magnum, known as the .300 Win Mag, is a big, bad magnum power cartridge. Its metric dimensions are 7.62x67mm. That makes it 23.8% bigger than the popular .308 Winchester at 7.62x51mm, and 6.3% bigger than the .30-06 at 7.62x63mm. It uses the same bullets as the .308 and .30-06, but it pushes them a greater distance downrange with a lot more velocity. While it has been surpassed in performance in recent years by technologically advanced newcomers, it remains the most popular .30 caliber magnum cartridge.

History of the .300 Win Mag Cartridge

The .300 Win Mag was not the first magnum cartridge, not even by a long shot. In fact, it was not even the first .30 caliber magnum in mass production. That distinction goes to the .300 H&H Magnum way back to 1925, followed by the .300 Weatherby Magnum appearing in 1944. The .300 Win Mag is actually the fourth magnum in a series of hard hitters and came out five years later in 1963. To bring the .300 Winchester Magnum to life, the Winchester Repeating Arms Company modified the heavyweight .338 Win Mag and re-released it in 1963 to use in the Model 70.

The short neck of the .300 Win Mag has been a controversial topic. Some ballistic experts suggest it could negatively affect accuracy. The neck of the .300 Win Mag is shorter than the diameter of the bullet it carries, however, in real-world results, this has little influence over the bullet’s accuracy. While so many of the other magnums of the early 20th century went the way of the buffalo, the .300 Win Mag, which had a slow and unheralded beginning, has stood the test of time and remains tremendously popular.

300 Win Mag Ammo Quick Answer Box:

• Is .300 Win Mag bigger than .308? The .300 Win Mag is larger than the popular .308 round, although both use the same .30  caliber bullets. The .300 Win Mag measures in at 7.62x67mm, while the .308 cartridge measures in at 7.62x51mm.

• What is the effective range of .300 Win Mag? With an optic zeroed at 270 yards, a factory 150gr .300 Win Mag bullet has an effective range of about 318 yards before needing hold-over to compensate for bullet drop. With an optic zeroed at 250 yards, a factory 180gr .300 Win Mag bullet has an effective range of about 300 yards before needing hold-over to compensate for bullet drop. The flat trajectory of the .300 Win Mag bullet allows skilled hunters with calibrated optics the ability to hit targets at 500 or even 1,000 yards away. 

• Is .300 Win Mag better for hunting deer than .223 Rem? You’ve likely heard both sides of this argument, .223 is too weak of a round for deer hunting, or .300 Win Mag is too powerful of a round for deer hunting. Neither are true. If you are hunting deer in the 100-300 yard range, a quality .223 round like Federal Fusion 62gr will put food on your table with careful shot placement. If you are commonly hunting deer at distances of 300 yards or greater, you may need the extra reach of a Magnum cartridge like the .300 Win Mag. 150gr Winchester Super-X Power-Point in .300 Win Mag is specifically designed to stop a deer in its tracks well beyond the 300 yard range with a zeroed optic.

.300 Win Mag Bullet Types

Magnum calibers are not for casual plinkers. They are pricey, well-engineered rounds and depending on your gun, they are often not pleasant to shoot. Did I mention that they are pricey? An average box of 20 rounds of .300 Win Mag is 3X the price of an average box of .223 Rem. If you are going to pull the trigger on a weapon chambered in Magnum ammo, you may want to consider how much you are willing to invest in it. 

On the bright side, the .300 Win Mag is common enough that pricing is kept to a reasonable level. There are a few of the more budget-friendly manufacturers that produce quality ammunition for it. Also, it is common enough that many of the economy-line rifles by leading manufacturers are now produced in the caliber.

You may find some standard FMJ ammunition produced in the Magnum caliber (and the amateur re-loader can definitely do so if they wish, since it uses the common .30 caliber bullet), but the most common economy target and training load is a soft point, ranging in weight from 150gr to 180gr. 

Soft Point

By far the most prolific bullet type on .300 Win Mag is the soft point. A well-balanced bullet which has a good ballistic coefficient, is easily produced en masse. It’s likely to be either be flat-based or boat-tail. Since it shares projectiles with its very common little brothers, it is easy to see it as a Big Block .308 and that seems apropos considering the velocity and energy it delivers. But this is not universally true; not all bullet weights carry energy as well as others. The 150gr screams out of the gate at .223 velocities. It delivers a TON of energy at the muzzle but drops precipitously after 200 yards.

However, the 180gr and 200gr samples hold onto much more energy at 500 yards.

Hollow Point

Like almost all other high powered rifle calibers, save the personal protection/defensive calibers, hollow points are generally reserved for precision and match usage only. Hollow point Magnum loads are less of a traditional hollow point and more of a divot. They are practically all boat-tail bullets, and on the heavier end of the spectrum, often in the 190gr-range.

Nosler Accubond

An interesting thing about the ammunition industry is how many of the major manufacturers use bullets made by other premium manufacturers (Nosler, Hornady, etc.) with their own proprietary blends of brass and propellants. It’s not uncommon to find this mixed brand assortment for .300 Win Mag, specifically in the Nosler bullet type.

Nosler AccuBond is very popular due to its excellent flight profile, accuracy, and lethal impact. It uses a unique bonding process that prevents voids in the bullet’s core, creating the most stable flight path possible.

The Best 300 Win Mag Ammo For Hunting

Hornady American Whitetail 300 Win Mag 150 Grain SP Interlock

Everyone wants to feel the excitement of bringing home something from the hunt on opening day. Hornady decided to increase hunter’s chances of putting meat in the freezer and antlers on the wall with their American Whitetail cartridge. This SP Interlock design keeps the core and jacket together on impact. It features a lead alloy core for improved penetration in dense targets. Screaming out of the barrel at 3,275 FPS, Hornady records 3572ft/lbs of energy at the muzzle and maintains almost 2,000ft/lbs of target dropping power out to 300 yards. 

Federal Vital-Shok 300 Win Mag 165 Grain Nosler Partition SP

Once again we see Federal Premium Ammunition utilizing the vicious Nosler Partition soft point. So why Partition? Sixty-five years of history must be on to something. Results don’t lie and hunters can be sure this round has slain a lot of game in that time. The partition is an ingenious design, using dual lead core with a copper partition separating the two. The leading core, the soft point, creates a wicked, irrecoverable wound. The aft core retains nearly all of its mass, hence all of its energy to push the bullet through the target.

Federal loads the Vital Shok with a 165gr Partition that has a great ballistic coefficient of 0.409 and screams out of the brake at 3,050fps and 3,408ft/lbs of energy! What a hammer.

Winchester Super-X 300 Winchester Magnum 150 Grain Power-Point

150gr loads are the top fuel dragsters of the .30 caliber bullet world and Winchester Super-X is no exception. Super-X PowerPoint ammo is a bonded soft point that is designed primarily for bringing down mid to larger sized game normally encountered in a forest environment.

150gr PowerPoint are extremely fast at the muzzle, generally in the ballpark of 3,250-3,300fps with around 3,500ft/lbs of energy. As previously discussed, 150gr bullets in .300 Win Mag scream out of the muzzle with enormous energy but begin to drop off after passing 300 yards. That being said, Winchester Super-X is consistent with other 150gr loads and still carries between 1,300-1,400ft/lbs at 500 yards. That may not be favorable for elk, but ample for taking down whitetail and antelope at a distance.

Federal Fusion 300 Winchester Magnum 180 Grain Fusion

Federal Fusion is a bullet designed specifically for deer hunting and the 180gr carries plenty of wallop for that use, well out to and past 500 yards. The design is a soft point bullet with a boat tail, possessing a tremendous ballistic coefficient of 0.485. It is considerably slower upon launch than the 150gr bullets, However, it maintains much more energy through the curve. It will pound targets with authority well out of the effective range of lesser rounds.

Is .300 Win Mag The Best Long Range Hunting Ammo?

It’s an easy question to answer. If .300 Win Mag checks all the boxes you need for hunting performance, go for it! A .300 Win Mag is a great addition to any sportsman’s gun locker, now more than ever. With a large variety of solid budget bolt guns with price tags sometimes dipping sub-$300 (sans optics). No, you’re not probably going to use these budget rifles at match shoots, but they aren’t made for that. The casual hunter will find these rifles are very well suited for one shot, maybe two, with the best 300 Win Mag ammo in a hunt. You won’t have to worry about having to track a wounded animal for hours later.

The .300 Win Mag offers a surprising amount of versatility for a Magnum cartridge. The 150gr SP rounds are capable of appealing to deer hunters. The heavier 180gr bullets are for those interested in bringing home big game. For the hand loader, the .300 Win Mag makes a ton of sense since as well.  Almost all rifle owners own either a .308 or .30-06 (most likely both) and the .30 caliber bullets are fully compatible.