.338 Lapua vs. .338 ARC: Caliber Bell Curve Opposites

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There’s a long-held belief among gun writers that the potential for commercial success of any cartridge over .30-inches in diameter is very limited. America, they’ll tell you, is a .30-caliber nation, and anything larger than that simply doesn’t draw the interest of hunters and shooters. And, honestly, history has shown this to be true. The .338 Winchester Magnum never touched the popularity of the .300 Winchester Magnum, and the .338 Federal, .340 Weatherby Magnum, .338 RPM, and .338 Remington Ultra Magnum all have loyal but relatively small fan bases.

The two .338 cartridges at either end of the power band seem to be drawing interest from hunters lately, though. In the heavyweight class, we have the .338 Lapua, a round originally designed for snipers that would split the difference between the .300 Winchester Magnum and .50 BMG. On the other end of the .338 spectrum is Hornady’s new .338 Advanced Rifle Cartridge (ARC), which fits in AR-15 rifles and short, light bolt guns. These are two very different rounds that have each carved their own niche in the hunting landscape. But where do they fit, and can .338 cartridges ever gain widespread popularity?

The .338 Lapua

In the early 1980s, the .338 Lapua was designed as a long-range sniper cartridge capable of effectively striking targets out to 1,500 yards. It’s based on a .416 Rigby case necked down to accept .338-inch bullets, and at various points in its 40-year history, it has been known as the .338/416, 8.58x71, .338 Lapua Magnum, and—most commonly—the .338 Lapua.

Whatever you call it, the cartridge is very potent. Original ballistics called for it to push a 250-grain bullet at 3,000 feet per second, but factory loads generally fall slightly below that figure. Hornady’s Precision Hunter .338 Lapua load sends a 250-grain ELD-X bullet downrange with a muzzle velocity of 2,800 feet per second, and Nosler offers a load that pushes a 250-grain Accubond bullet at an advertised velocity of 2,850 fps. Nosler also offers a 300-grain Accubond .338 Lapua load (2,650 fps). Barnes offers a lead-free Lapua load, which drives a 280-grain LRX monometal bullet at 2,600 fps.

All these rounds produce over two tons of muzzle energy, and some are well above 4,600 foot-pounds. Factory .338 Lapua hunting loads generally beat .375 H&H Magnum muzzle energy figures, and the use of high BC bullets means that the Lapua carries that energy efficiently to extended ranges. For example, the 270-grain Hornady ELD-X  factory load has a G1 BC of .757, and that load carries over 4,000 foot-pounds of energy to almost 200 yards. When zeroed at 200 yards, the bullet drops around -19.7 inches at 400 yards. The company’s 178-grain ELD-X .30-06 load, for comparison, drops around -22.2 inches at 400 yards when zeroed at 200 yards, and the Lapua carries about 300 more foot-pounds of energy at 400 yards than the .30-06 generates at the muzzle. So yes, the .338 Lapua is a thumper.

The Lapua thumps at both ends, though. Most .338 Lapua hunting rifles weigh between 8 and 10 pounds, and while that is more than most hunting guns, the added mass helps minimize recoil. Most every .338 Lapua rifle also comes with a brake, and this helps keep recoil at or under 40 foot-pounds. At roughly twice the recoil of a .30-06 that’s no gentle shove, but it’s on par with a 9-pound unbraked .375 H&H magnum and about 20% less than a 10-pound .416 Rigby. Muzzle blast is substantial, and you won’t make any friends on the range, but a braked .338 Lapua is manageable to shoot if you are comfortable with stout recoil.

In recent years, more gun companies have begun offering .338 Lapua rifles for hunters, and these include the Weatherby Mark V Accumark, Savage 110 Long Range Hunter, and Christensen Arms’ Modern Precision Rifle. Ruger also offers a .338 Lapua version of their RPR that’s more target-centric and weighs 13-pounds.

There are those that argue you can’t be “overgunned” for hunting any animal, and they would certainly like the Lapua. While I think it’s certainly more than you need for deer, the .338 Lapua will work so long as you can handle the recoil and gun weight. But where these rifles make the most sense is hunting very large game at extended distances. Elk are notoriously tough, and cross-canyon shots are the norm in many areas. In those cases, a Lapua will work fine. It’s also suitable for big bears and large African game. Then again, so are the .300 PRC, .338 Win Mag, and other cartridges with less kick.

The real draw to the .338 Lapua, at least in my mind, is for the hunter who likes to shoot long distances. If you want to hit targets at 1,500 yards plus with the same rifle you carry while hunting, then the .338 Lapua will work. Factory loads are not inexpensive and run between $5.00 and $8.00 per round on average, although you can occasionally find ammo that costs less.

The .338 ARC

The .338 ARC project began when the Department of Defense asked the folks at Hornady to develop a subsonic round that was more potent than other cartridges for the AR-15. This project was shelved and the company instead began developing the 6mm ARC and .22 ARC. The release of both rounds predates the .338 ARC.

However, the .338 ARC was too good to sit on the shelf for very long. It’s a rather unusual-looking cartridge that appears to have been designed by the ammo engineers on Easter Island, but that big bullet/small case design works well.

Hornady has a habit of building cartridges around bullets, not the reverse. In the case of the .338 ARC that bullet is the 307-grain Sub-X .338-inch bullet. It’s designed to expand and reliably transfer energy even at very low velocities, and anyone who has ever shot that bullet on steel or game knows that it hits very hard. The ballistics don’t blow your hair back like the .338 Lapua, but with a muzzle velocity of 1,050 fps from a short (16-inch) barrel, the Sub-X load generates 752 foot-pounds of energy.

The .338 Arc’s main rival will likely be the .300 Blackout, and Hornady offers a 190-grain Sub-X load for that cartridge. Both the Blackout and .338 ARC fit in AR-15 platform rifles, but the .338 ARC hits with more authority. The .300 Blackout load travels at the same velocity as the .338 ARC (1,050 fps) but generates just 465 foot-pounds of energy at the muzzle. The .338 ARC load carries more energy than that at 400 yards. At 200 yards—a far more realistic maximum effective range for subsonic ammunition—the .338 Arc carries 605 foot-pounds of energy.

This is important because many hunters want an AR-15 that is suitable for hunting hogs and deer-sized game. The .338 ARC is simply better suited for that than the .300 Blackout, and the mild-mannered midbore is equally fun to shoot. This is due in part to the .338 ARC’s relatively tame demeanor for such a capable cartridge, but it’s also because it doesn’t take a great deal of fiddling to make a .338 ARC run with both supersonic and subsonic ammo and with or without a suppressor.

Without getting too deep in the weeds, this is due in part to the .338 ARC’s higher operating pressures with subsonic ammo. The .338 ARC operates at pressures in the low 40,000/high 30,000 psi range with subsonic ammo and right at 50,000 psi with supersonic ammunition. The pressure gap is far less than the 25,000 or so psi variation in .300 Blackout between super and subsonic ammunition. What this means in practical terms is that .338 ARC rifles tend to run well with subsonic and supersonic ammunition with or without a suppressor, and that simplicity is a real benefit for hunters.

Can you match the .338 ARC’s terminal performance with other subsonic cartridges? Certainly, but not in the same small platform. The 8.6 Blackout which utilizes a modified 6.5 Creedmoor case also fires .338-inch bullets at subsonic velocities, but it requires a larger AR-10 platform autoloader.

The .338 ARC isn’t just designed for autoloading rifles, though. It is also suitable for micro-action bolt guns and can be built very light. Recoil is minimal and manageable and with a suppressor in place this cartridge is a dream to shoot. In lightweight rifles, it’s a great backcountry cartridge for making shots under a couple hundred yards on deer-sized game, and a suppressed .338 ARC AR-15 with a thermal optic would be just the ticket for hunting hogs under cover of darkness. Since both super and subsonic loads are available from Hornady you can tune your rifle to the conditions and the game.

A Tale of Two .338s

This article was not, of course, a direct comparison between the .338 Lapua and .338 ARC. That would make about as much sense as comparing a Ford Mustang with a Massey Ferguson tractor. They’re two entirely different tools for two very different jobs. However, I think there’s a place in the hunter’s gun safe for the Lapua, the ARC, or even both. The ARC is certainly the cheaper to shoot (Hornady super and subsonic loads for the .338 ARC cost under $2.00 per round), but the Lapua offers the ability to kill the largest game at extended distances.

The .338 market has long been considered hostile ground. No cartridge, we were told, could be a best-seller in this mid-bore range. I think the .338 Lapua and the .338 ARC have the best chance of being the superstars of the .338 market, and both are ideal for hunting—just so long as you know what the .338 you choose was meant to do.

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