300 Winchester Magnum

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The 300 Winchester Magnum is a long action belted magnum introduced in 1963 by Winchester Repeating Arms. It is a necked down, shortened, and slightly blown out cartridge based on the parent 375 H&H. The 300 Win Mag has always been considered one of the great hunting cartridges, and with the current selection of bullets, better suited for long-range shooting, it has come into its own. We have included a SAAMI chamber drawing in this cartridge guide. Although the 300 Win Mag can benefit slightly from a custom chamber it does very well in SAAMI form. For most of its existence, it has been stuck with mediocre long-range bullets however this cartridge guide is going to focus on long-range hunting and shooting loads. It will focus on bullets from 200-230 grains and the powders most appropriate for them. Lighter bullets are not ideal for long-range hunting in a 30 caliber. Although heavier bullets can be used we feel they are better suited in larger capacity cartridges.

300 300 Winchester Magnum

DISCLAIMER: This is a guide. Everything listed within is for information purposes only. All loads should be worked up carefully. We have seen loads require as much as two grains of charge weight adjustment from one powder lot to another. We have seen as much as five grains of powder adjustment required between different brands of brass. Failure to start low could result in damaged equipment or injury. USE AT YOUR OWN RISK.

SAAMI 300 Winchester Magnum

300 Winchester Magnum Cartridge Case

First, let’s discuss the case itself. Many opponents of the cartridge will want to discuss the belt as being a hindrance but in real-world use, it is of little concern. If you treat the cartridge like any other and ignore the belt you will never even know it exists other than cosmetically. We are advocates of letting cases growing during the first few firings to the point where the bolt closure force gets noticeably more difficult to close and then set our dies up for a .002” shoulder bump. If you do this with the 300WM it will behave like every non-belted cartridge. In our opinion, this takes care of one of the so-called issues with the cartridge.

SAAMI1 300 Winchester Magnum

The second issue is the SAAMI spec overall cartridge length. With a SAAMI spec of 3.4” overall length, it is a worthy concern. For long-range hunting and shooting, we typically don’t use factory ammo and this guide is for reloading so we are going to consider this a moot point. As discussed above we have found the SAAMI chamber itself to be satisfactory for reloading. With bullets like the 215 and 230 Berger, the chamber has plenty of room to avoid using precious case capacity when the bullets are seated at or near the lands. While the SAAMI spec chamber is sufficient for the shorter bearing surface bullets like the two Bergers mentioned it does not have the freebore required to get the full use of the case with longer bearing surface bullets like the ELDs. We would recommend anywhere from .200” to .250” depending on the bullet.

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Case Capacities

With those two issues out of the way, let’s get on with the guide. The case capacities are included in the image below. Depending on the brand capacity will be between 89 and 95 grains of water to the top of the neck. We like to use this number, as “usable” capacity is arbitrary. This puts the 300WM roughly 6-12 grains above the 300WSM, equal to or slightly less than the 300 PRC, and 2-13 grains below the 30 Nosler depending on brass brands.

Case capacities image1 300 Winchester Magnum

Our Go-To Load Recipes

Now let’s talk about loads that have worked well for us. First and foremost is H1000 with a 215 Berger. This load shoots very well in almost every rifle, from factory rifles to customs. Pick your favorite magnum primer, start at 73 grains of H1000 with a Berger seated at the lands and work up to pressure. You will usually find pressure between 76 and 79 grains. Case capacity and power lots can and do have a huge effect on this as mentioned above. Take the most accurate charge and do seating depth testing. In our experience, they usually prefer from at the lands to .040” off. Some have had great luck farther from the lands.

As far as actual load development methods we have a couple of great videos on our YouTube channel.

Our Favorite Berger Bullets

The 215 Berger has proven to be a very effective hunting bullet and performs very well near and far. This is a favorite combination of mine as well as many forum members. Next, we will mention the 210 Berger HVLD. For load development with the 210 HVLD, you can just do the same as the 215 Berger. This is another great combination but as you can see in the chart below it most likely will not have the same ballistic performance. The lower ballistic coefficient and longer bearing surface most likely will not let it outperform the 215 Berger.

drifts 300 Winchester Magnum

drops 300 Winchester Magnum

The 225 Hornady ELD-M and the Berger 230 hybrid target and Hybrid OTM are great bullet options for those wanting a little larger bullet. These bullets have performed very well on game and are great for shooting steel. We have a couple of loads listed in the loads chart. As with any data, start low and work up. These will keep up with the 215 Berger in drift but will not be as flat shooting.

loads 300 Winchester Magnum

Let’s Talk Powders

There are many great powders for this case capacity and bullet weight range. Hodgdon’s powders have been great performers for many years. H1000 and Retumbo will be the best powders for the bullet weights we are covering. H4831SC can be great as well for the lighter bullets in that 200-grain range but is getting to be on the fast side.

Alliant powders have always been a favorite of many 300 Win Mag reloaders. Reloder 22 and 25 have been great but their temperature instability makes them unusable for taking ethical long-range shots, at game, in changing conditions. Whereas, Reloder 23 is very temp stable and has a similar burn rate to H4831SC. Reloder 26 is not listed as temperature stable but in my experience has been in many cartridges including those in the case capacity range of the 300 Win Mag.

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Vihtavuori has a few great options. N565 will be very similar to H1000 in burn rate and N570 will be very similar to Retumbo. Both N565 and N570 do very well with bullets from 200 grains to 230 grains. They typically yield slightly faster speeds than their Hodgdon counterparts.

powder 300 Winchester Magnum

Other Bullet Options For The 300 Win Mag

Though we have discussed a few bullets we have the most experience with there are several other great options. Cutting Edge bullets makes three bullets in the weight range we are discussing with the 220, 230, and 240 grain Lazers. These bullets are bore rider, solid copper designs, and will typically yield more velocity over a typical lead core bullet as well as other monolithics. They are designed so that the nose of the bullet will fracture and three petals will radiate from the core causing a wound channel somewhat similar to a typical fragmenting lead core bullet. At the same time, the core of the bullet continues to penetrate deeply into the animal often with an exit many desire.

Other Berger bullets worth discussing are the 200.20x and 205 Elite Hunter. The Elite hunter will perform much like other Berger “hunting” bullets. The 200.20x will perform much like the 215 Hybrid. In use, it will be very difficult to tell the terminal performance apart. They will penetrate a few inches and rapidly expand causing violent and rapid shock to the animal’s vitals.

Hornady Bullets

Hornady bullets worth discussing are the 208 ELD-M, 200 ELD-X, 212 ELD-X, and 220 ELD-X. These bullets will have a very similar terminal performance to the Bergers.

Nosler Bullets

Nosler makes many great bullets but the one we will include in this guide is the 210 grain Long Range Accubond. This bullet is the typical bonded bullet Nosler is known for. This bullet is one of Nosler’s best ballistically performing bullets and still gives the “mushroom” many hunters have come to love.

Barnes Bullets

Last but not least we will talk about the two Barnes bullets that best fit this guide. The 200 and 212-grain LRX long-range hunting bullets give a beautiful flower petal expansion that many Barnes fans have come to love. The one issue we have seen with them is the lack of expansion at lower velocities. Lower velocity limits for expansion are always a consideration but with the inferior ballistic performance of the Barnes, you will need to pay closer attention. There are too many bullets out there to discuss them all but we feel this covers the more popular options.

bullet 300 Winchester Magnum
Left to right:210 Nosler Long Range Accubond, 200 Barnes LRX, 208 Hornady ELD-M, 212 Hornady ELD-X, 225 Hornady ELD-M, 230 Hornady A-Tip, 220 CEB Lazer, 230 CEB Lazer, 240 CEB Lazer, 200 Sierra Match King, 230 Sierra Match King, 205 Berger Elite Hunter, 215 Berger Hybrid, 220 Berger Long Range Hybrid Target, 230 Berger Hybrid, 245 Berger EOL.

Primer Options

Any magnum primer will work well with the 300 Win Mag with the most commonly used being the Federal 215 Match and the CCI 250. In use, I can’t say one is a better performer. I usually pick one and do load development with it. If I cannot get the velocity extreme spreads or the accuracy I desire I will swap to the other. I have stopped swapping “just to see” because it rarely gets better in my experience. I feel to see the best results from a primer you need to do a full load workup.

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DSC02942 300 Winchester Magnum

Reloading Dies

Any good set of reloading dies will work but we have come to prefer full-length “S” bushing dies with a micrometer seater. Redding dies have become our preference. Hornady makes a great set of bushing dies with a micrometer seater, often at half the cost. Both have made great consistent ammo. We will have a video on our YouTube channel discussing the different dies and why you might choose one over another.

trailrider121 rifle 300 Winchester Magnum
Trailrider121’s 300 Win Mag.

Rifle Recommendations

For those looking at factory rifles chambered in 300 Win Mag, there are only a few we can recommend due to magazine restrictions of most. Christensen Arms makes many great models chambered in 300 Win Mag and one of them will surely fit your needs. We have shot many different models and all have exceeded expectations. These rifles give custom performance at a fraction of the cost.

Christensen Rifles

Fierce offers multiple models that would suit the needs of most as well. I have shot the Edge models and the Rival. Both are great if in your budget.

Fierce Rifles

Bergara also offers several great rifles with 3.7” magazine boxes, which is what you need to take full advantage of the cartridge. Stick with a BDL floorplate model and you will have the magazine room.

Bergara Rifles

There are many other great factory rifles however most have short magazine boxes and will not allow most of the bullets we discussed above to be seated where they need to be to allow full use of the case capacity.

Check Out Our Sponsors For Your Rifle

If a custom 300 Win Mag is what you are after there are almost an infinite amount of options. Take a look at our sponsor page. There are a few great rifle builder and gunsmith options. We also have some sponsors that make great components. Whether you are looking for a turnkey custom or you want to collect the parts and have one built our sponsors have you covered.

rackcity elk 300 Winchester Magnum
Rackcity with an elk taken with his 300 Win Mag.

A Proven Contender

In a day and age when everyone is after the latest and greatest thing, the 300 Win Mag is still more than capable of keeping up with the competition. Not only can it keep up, but it also has several advantages such as almost countless factory ammo options. This may one day get you out of a bind if you happened to have an issue with your ammo and need ammo for a hunt. If you found this guide in preparation for your next rifle the 300 win mag more than deserves your consideration.

Click here to join the conversation on the forum and read member’s input on loads that have worked for them.

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Ethan Smith is a seasoned marine veteran, professional blogger, witty and edgy writer, and an avid hunter. He spent a great deal of his childhood years around the Apache-Sitgreaves National Forest in Arizona. Watching active hunters practise their craft initiated him into the world of hunting and rubrics of outdoor life. He also honed his writing skills by sharing his outdoor experiences with fellow schoolmates through their high school’s magazine. Further along the way, the US Marine Corps got wind of his excellent combination of skills and sought to put them into good use by employing him as a combat correspondent. He now shares his income from this prestigious job with his wife and one kid. Read more >>