A Reader Asks: What’s The Best Long-Range Rifle Cartridge?

Don writes:

I have heard good things about the 6.5 Creedmoor as far as accuracy but also know ammo manufacturing in this caliber are very limited.  I am looking to find a gun/caliber that has a longer range than my POF AR15.  I love my AR and have a great time shooting it but really think I would also enjoy the challenge of longer range accuracy shooting.  I like the POF brand and see they sell a 6.5 Creedmoor gun with a 20” barrel.

What other calibers you would recommend looking at?

Don,

I’ve done some long-range shooting myself, and I’ve sometimes reached the limits of 5.56  performance when I’m trying to ring the gong at 600 or 800 yards.

6.5mm bullets are a better choice, but thanks to economics they’ve never been as popular in the U.S. as .30 caliber cartridges have been (while 7.62 projectiles are churned out 24/7 thanks to government contracts, 6.5 bullets are purely civilian). They’ve got an inherent ballistic advantage over 7.62 and 5.56mm bullets because their long knitting-needle shaped bullets have high ballistic coefficients and high sectional density.

This makes them outstanding for long-range precision shooting at 600 yards and beyond, and they’re also excellent for hunting anything from varmints to antelope and large deer. Hunters in Sweden still use their antique 6.5x55mm Model 1892 Mausers to take deer, moose and even bear.

The 6.5 Grendel and larger-diameter 6.8 SPC are two high-pressure intermediate cartridges that can be fired through a standard AR-15 action. With substantially more energy and long-range accuracy than the 5.56×45, they’re dynamite on deer and antelope. They both propel 120-grain bullets at 2500-2600 fps, and they both shoot flatter than a .308 with considerably less recoil.

There’s a cost to shooting these higher-intensity cartridges through AR-15 actions, however. The produce more bolt thrust than the AR-15 bolt lugs were designed for, especially since the locking lugs must be slightly smaller, to accommodate the larger case heads of these cartridges. Bolt failure occasionally occurs even in good AR-15 uppers in these calibers.

The 6.5mm Creedmoor is a longer cartridge (72mm overall, compared to 58mm for the 6.5 Grendel) that can’t fit through an AR-15 action, but works well in the AR-10 or any length bolt-action. The 6.5 Creedmoor pushes a 120-grain bullet at 3,000 fps, which is a substantial performance boost over the shorter Grendel, and with the high ballistic coefficient this allows some really long-range fun.

It’s ballistically similar to my favorite long-action rifle cartridge, the .270 Winchester, but it’s a full half-inch shorter and has longer, more aerodynamic bullets.

Ammunition choices for all of these 6mm-class cartridges are limited. Since they haven’t been adopted by any armed forces, they’re only available from a few manufacturers and the ammo costs almost $1 a round. The 6.8 SPC is in the same boat, and 6.5 Creedmoor runs $1.25 a round or more. In addition, there are often multiple variations of each caliber and making sure the ammo matches your firearm can be a pain.

The 6.5 Creedmoor is clearly the better long-range choice, if you’re going to use a bolt-action or AR-10 platform. 6.5mm bullets are commonly available for handloading your own ammunition, and if you’re looking for the best accuracy you’ll eventually end up handloading your own fired brass.

There are hotter 6.5mm rounds out there. The .264 Winchester Magnum and the 6.5mm Remington Magnum are both excellent performers, with velocities 200 or 300 fps faster than the 6.5mm Creedmoor, but they’re both relatively unpopular and they both have a reputation for wearing out barrels very quickly. If you really want that extra performance, you’ll have to custom-order a rifle and handload your own ammunition.

The 6.5mm Creedmoor is probably the best choice for a really flat-shooting cartridge of reasonable size. Don’t get a barrel shorter than 20 inches. For the best long-range performance you might want a 24-inch barrel, but those can be pretty unwieldy on an AR-10.

But for the longest-range shooting, when you’re shooting out to a klick and beyond, there’s really only one ultimate choice: the .338 Lapua. The mighty .338 treated me to the best day of shooting of my whole life, finally ringing the gong at 1140 yards. Two boxes of 250-grain BTHPs also gave me a bruised, livid shoulder that ached for days.

.338 Lapuas aren’t for everyone. The rifles cost a fortune, kick like mules, and shoot five-dollar bills out the barrel. They’re so powerful they can beat you senseless, and this power is completely wasted if your target isn’t either 1) the size of a rhinoceros or 2) at least half a mile away.

On top of that, the muzzle blast and overpressure are so obnoxious that the shooters near you at the firing line will hate your guts, at least until you let them fire a few rounds through it. After that they’ll love you.

Definitely not for everyone. But if you’ve got the means (and access to a really really long shooting range) there’s nothing like it in the world.

Another dark-horse candidate for really long-range shooting is the common .243 Winchester. Many extreme-range shooting enthusiasts handload their .243s to extreme velocities (and burn out their barrels in less than 1,000 shots) which has led many competitions to set a muzzle velocity limits to discourage this. Apparently the .243 can be extremely accurate at long range, as long as you’re willing to replace the barrel after three or four matches.

But I think you’ve already focused on a great choice in the 6.5 Creedmoor. Its one drawback is that it’s not a ‘Wal-Mart’ caliber, but it’s widely available from online retailers.

Best of luck!