There are many options for magnum long-range cartridges, but two commonly compared are the .300 Winchester Magnum and the .338 Lapua. This is understandable, as each has been around for decades and has seen military service by some of the most legendary snipers of their time. Before pulling the trigger on an expensive rifle chambered in one of these cartridges, it pays to know the pros and cons of each. Let’s take a look at each in depth.
.300 Winchester Magnum
The .300 Win. Mag. and its story began in 1963, when America was well within its .30-caliber obsession. For ages, we considered this the ideal bullet diameter and creating a better long-distance round involved little more than driving it from a magnum case. Early .30-caliber magnums offered flatter trajectories and delivered more energy downrange — something hunters believed increased their killing power. Inspired by Roy Weatherby’s magnums, Winchester used the same .375 H&H case to form their high-velocity .30 caliber creation, just as it did its .338 Win. Mag.
The new cartridge would push bullets weighing 150 to 220 grains faster than most offerings at the time while fitting in a standard long-action receiver. It hit the scene with intentions of attracting hunters, as the 150-grain loads gave them flatter trajectories than cartridges like .308 Win. or .30-06 Springfield, and the 180-grain loads delivered more energy downrange. However, as .30-caliber match bullets were already being used in competition, they soon found interest within the long-range competition community and, eventually, military service. Cartridges like the MK 248 Mod 1, paired with the M24 sniper rifle, extend the range of our marksmen without adding substantial recoil or signature. However, it is worth noting that this load is considered overpressure under SAAMI standards.
.300 Winchester Magnum Specs
- Parent Case: .375 H&H
- Case Capacity: 92 Grains H2O
- Shoulder Angle: 25 Degrees
- Max COAL: 3.340 inches
- SAAMI Twist Rate: 1:10 inches
- Bullet Weight: 150 to 200 grains (common)
- Powders: Medium to Slow — Varget to Staball HD
Inside the .300 Winchester Magnum
A look under the hood helps us understand where each cartridge comes into its own, as well as why they sometimes overlap. The .300 Win. Mag. was designed with standard long actions in mind, as its creators wanted it to be a plug-and-play option for rifle manufacturers. Most of the work was simply chambering a 1:10 twist .30-caliber barrel, and using a magnum (.540”) bolt face.
With a capacity of roughly 92 grains of water, there is room for enough propellant to drive 150-grain bullets over 3,200 fps. On the other end of the spectrum, we can expect a 200-grainer to leave the muzzle at a respectable 2,800-plus FPS. Either load yields around 3,400 foot-pounds of muzzle energy.
This cartridge does indeed have a lot going for it, but it has some outdated features — especially its belted case. Over the years, we’ve found that this isn’t necessary to withstand high pressure, and headspacing off the belt reduces consistency and accuracy. To understand the problem, envision trying to hold a pencil straight by the eraser, then you’ll get why the industry essentially abandoned this case design. Fortunately for the .300 Win. Mag., when chambered with tighter tolerances, It’s possible to set headspace off the 25-degree shoulder — which is steeper than previous cartridges like the .30/06 and .300 H&H Magnum.
.338 Lapua Magnum
The .338 Lapua Magnum was born in the 1980s from the need for a long-distance anti-material rifle round. Cartridges like the 7.62×51 weren’t up to the task, and using .50 BMG required a crew-served weapon at the time. Research Armament Industries worked with several companies to develop a solution based on the .416 Rigby case, but ran into pressure-related problems. Nammo Lapua Oy or, as it’s more simply known, Lapua, got the cartridge over the finish line and we now know it as the .338 Lapua Magnum.
The final case design holds roughly 115 grains of water. This leaves enough propellant space to push 230-grain bullets beyond 3,000 FPS and a 300-grain projectile at around 2,700 FPS. This generates a respective 4,995 ft./lbs and 4,855 ft./lbs of muzzle energy. A 250-grain load saw international service nearly immediately, with several other countries adopting or creating rifles to follow suit.
Like nearly every other military cartridge, the .338 Lapua Magnum found favor with civilians. Video game lore and its use in the Global War on Terror are largely responsible for its popularity. Predominantly a target round, most users turn to it for engagements beyond 1,000 yards — typically when the “mile shot” is on the table. Its initial 250-grain loading is still the most popular, but the market includes options as light as 230 grains and as heavy as 300 grains, with the latter comfortably taking the second-most-popular slot.
Today, as long-range hunting has become more prevalent, some are taking their .338s afield when they need to send heavier bullets at longer distances. Therefore, most ammo manufacturers also offer at least one hunting-specific load, and there are even a few lightweight factory rifles available to sling them.
.338 Lapua Magnum Specs
- Parent Case: .416 Rigby
- Case Capacity: 115 Grains H2O
- Shoulder Angle: 20 degrees
- Max COAL: 3.681 inches
- SAAMI Twist Rate: 1:10 inches
- Bullet Weight: 200 to 300 grains (common)
- Powders: Slow — H4350 to US869
Front Lines First
The .338 Lapua Mag wasn’t built with the civilian market in mind, so less thought was put into making it fit commercially available guns. To that end, most manufacturers turn to a magnum action when building a rifle to chamber it, or, at the very least, a heavily modified standard long action. The .416-based cartridge also needs a .590-inch bolt face, which is larger than the .532-inch bolt face used for standard magnums.
It appears there’s no comparison between the two in terms of overall downrange energy, but that’s only part of the story. The performance of the .338 Lapua Mag. does come at a price. Feeding a .338 LM is often to the tune of $6 per round — or more for match-grade fodder. Also, the .338 produces more felt recoil, so if all things are equal, the Lapua is going to beat you up harder than the Winchester. On the bright side, it does all of this without a belt, simplifying the design and making it more inherently accurate with standard chambers.
Close DOPE
So, if they are both used for extreme-long-range shooting, how do the cartridges compare? Let’s look at the .300’s 200- and 220-grain loads and the Lapua’s 250- and 300-grain offerings. The charts below represent cartridges fired at sea level on a 59-degree day with a full value 10 MPH wind. For the 300 Win. Mag., I chose a Berger Hybrid target for the 200-grain (.616 G1) and a Sierra MatchKing for the 220-grain load (.629 G1). As for the .338 Lapua, I went with a Hornady BTHP for the 250-grain load (.670 G1) and a Lapua Scenar for the 300-grain load (.736 G1). Velocities were derived from factory specs or, where necessary, from perceived maximum safe handloading data.
As you can see, all four keep pace with each other through the wind at 500 yards, and the drop is pretty close, too. This continues out to 1,000 yards. However, when we look at the 1,500-yard data, the two diverge. Both .300 Win. Mag. loads have gone transonic by now, but the .338 Lapua loads are still supersonic. At this point, the .338 loads have experienced about 12 and 32 inches less of wind drift than either .300 Win. Mag load. Considering how much wind conditions can change over that flight path, this is considerable. Further, at 1,500 yards, the .338 Lapua 300-grain load delivers nearly twice the energy of the .300 Win. Mag.
Savings at the Press
Both of these precision cartridges are likely to be reloaded by serious shooters. The good news is that both will fit into a standard press; if you’re already set up, all you need are dies and components. Likewise, they use many of the same powders. For a straight-line comparison, I’ll use Hodgdon’s H 1000, as it appears in Hornady’s 12th edition, for both the .300 Win. Mag. data with 200-grain bullets and the .338 Lapua Mag data with 300s. To push the Win. Mag. to the max, it’ll take roughly 76 grains of propellant. Redlining the .338 takes 89 grains, or about 20 percent more. Given the expense of powder, one must ask whether one needs the extra reach. Likewise, .338” bullets can cost twice as much as .308s. While you can cut costs by reloading both, the .300 Win. Mag. is certainly the more economical option.
Final Thoughts
So, who should buy which? Well, you’ll find more hunting ammo and rifles for the .300 Win. Mag., and more target guns and ammo for the .338 LM, but there is plenty of overlap, too. Both are nearly equal at bucking the wind inside of 1,000 yards, so stepping up to the .338 if you already have a .300 doesn’t provide much benefit. If all of your shooting is inside of 1,000 yards, the Win. Mag. is more sensible. If you plan on focusing on distances out to a mile, and you’re limited to factory choices, the Lapua Mag. is going to be more your speed. However, it’s worth noting that almost no serious ELR competitors are using it anymore, yet custom .300 Win. Mags are still very common. This is because many feel that a .300 with a quality match chamber offers more balanced performance with less recoil — something that can certainly be a factor over the course of an ELR match. The answer really comes down to how far you plan to shoot, how much you want to carry, and how much you’re willing to spend.
When the .300 Win. Mag. is the best choice
- When most shots are within 1,500 yards
- When factory rifle availability is important
- When hunting will be your primary use.
When .338 Lapua is the best choice
- When you plan on shooting to 1,500 yards and beyond.
- When you plan on buying a custom or semi-custom rifle.
- When you might tinker with ELR.
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