Top AR-15 Cartridges for Long Range Shooting

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Shooting far with AR-15s is something of a stunt. However, like Evel Knievel, the guys that do it have become spectacularly capable at that stunt. Rifle components and configuration are important, but there’s one crucial characteristic for shooting long with an AR-15: You must be using the right cartridge and projectile. Creating long-range cartridges that fit inside AR-15 actions is a challenge. You’ve got to have a well-blended balance of cartridge case capacity, bore diameter, bullet aerodynamics, and velocity. While the AR-15’s original 5.56 NATO/.223 Remington cartridge has been tweaked and modified in an effort to make it long-range-capable, there are modern cartridges that trounce it. So, for the purposes of this article, we’re going to use the 5.56 NATO as the benchmark and demonstrate that other cartridges are superior.

First, we must define long range. Let’s keep it simple and call it 1,000 yards. That’s our holy grail of AR-15 reach, the ultimate destination at which we’d like to precisely place shots. Just for fun, we’ll also detail max distance before a bullet slows down to transonic speed. Transonic, of course, is the sound barrier. Supersonic means a bullet is going faster than the speed of sound. Subsonic means it’s going slower. Transonic means the bullet is traveling at the same rate as sound waves. Why is that important? Because when a bullet goes transonic, it becomes unstable. Accuracy goes to pot. When a projectile travels shoulder-to-shoulder with a bunch of sound waves, those vibrations destabilize it. Projectiles previously spinning like a perfectly balanced top will wobble, yaw, and sometimes even tumble end over end. Interesting stuff. For our purposes, we’re going to exercise a little executive authority and establish the transonic threshold as 1,125 fps. That’s a forgiving number at or fractionally above true transonic, depending on air temperature. It’s also easy to crunch in ballistic calculators. Atmospheric conditions are also important when calculating aerodynamic performance; we’ll go with the standard of 59 degrees Fahrenheit at sea level with barometric pressure at 29.92 inch mercury (inHg). Whatever the distance is at which a top-notch, long-range bullet from a given cartridge goes transonic, that’s our max effective range with that cartridge/projectile combination. This will enable us to definitively compare several of the popular, capable modern AR-15 cartridges on the market. We’ll also look at wind drift and retained energy. Those numbers will help showcase best-in-class capability.

Contenders

There are four primary players in the long-range AR-15 game. They are .224 Valkyrie, 22 Nosler, 6mm ARC, and 6.5 Grendel. Each has enough case capacity to push aerodynamic bullets with high ballistic coefficients to useful velocities. Which is best? Let’s establish a base line using the 5.56 NATO and compare each to it. We’ll also throw in a few random notes on available factory ammo, appropriate magazines, barrel conversion ease, and so forth. Then, you decide. Competitors in Service Rifle and Palma type matches use 80- to 90-grain high-BC bullets in the 5.56 NATO. Such projectiles have long, sleek profiles and do a reasonably good job at 1,000 yards. However, they have one crippling characteristic: They’re not compatible with AR-15 magazines. When using them, you have to single-load your rifle. That effectively squelches the practical effectiveness of such bullets. For the purposes of this article, we’re going to keep to magazine-compatible loads.

In the 5.56, there are a few bullets that provide best-in-class performance at extended ranges. After working rather extensively with most of them, my favorite is Sierra’s 77-grain Tipped MatchKing, handloaded or as factory-loaded by Black Hills Ammunition. With a G1 BC of .420 and an advertised muzzle velocity of 2,750 fps, it’s better for long range than just about any other 5.56 factory load. Muzzle energy is right at 1,300 ft-lbs. In standardized sea-level atmospherics, the projectile stays supersonic to nearly 925 yards. That’s darned impressive, but it doesn’t quite make the 1,000-yard cut. When zeroed at 200 yards, the 77-grain TMK drops 419 inches at 1,000 yards and drifts 129 inches in a 10-mph crosswind. At 1,000 yards, it’s poking along at 1,057 fps and carrying just 191 ft-lbs of energy. So that’s your benchmark: A 5.56 NATO with premium long-range ammo that’s still mag-compatible. For those wondering, 5.56 NATO ammo is loaded to higher pressures than its .223 Remington twin, so we’re showing best-possible long-range performance here. Now, let’s take a look at some modern contenders.

.224 VALKYRIE

This fine little cartridge was engineered for use in the AR-15, specifically to overcome all the long-range issues of the 5.56 NATO. It was introduced in 2017. The parent case is the 6.8 SPC, so it has a larger diameter body. As a result, even though the .224 Valkyrie case is shorter, it holds more powder than the 5.56 case does. AR mags comfortably house and feed cartridges loaded with the longest, sleekest .22 centerfire bullets available. Federal designed the “Valk” and spec’d it with a 90-grain Sierra MatchKing bullet right out the gate. This projectile has a G1 BC of .563, which is darned impressive in the .224-caliber world. Factory ammunition is advertised to produce 2,700 fps in 24-inch barrels, generating 1,463 ft-lbs of muzzle energy. In sea-level atmospheric conditions, the 90-grain SMK stays supersonic to right near 1,200 yards. That’s a tremendous improvement over the 5.56 NATO. When zeroed at 200 yards, the 90-grain TMK drops 336 inches at 1,000 yards and drifts 87 inches in a 10-mph crosswind. Compare the numbers. That’s a ton better performance than the 5.56 can provide. Velocity at 1,000 yards is 1,292 fps, and the bullet is packing 333 ft-lbs of energy. This is a legitimate 1,000-yard AR-15 cartridge.

22 NOSLER

Nosler’s innovative engineers cooked up this excellent little AR-15 cartridge in 2017, the same year as the .224 Valkyrie. Unlike the Valkyrie, though, the 22 Nosler uses an original case design, and its rebated rim is the same diameter as the standard 5.56’s rim. This means shooters can simply install a 22 Nosler barrel on an existing AR-15 in 5.56, and they’re off to the range — no special bolt needed. Case capacity is a tad greater than the .224 Valkyrie, too, so the 22 Nosler can push bullets in any given weight a bit faster. However, standard rifling twist rate is 1:8, so the 22 Nosler doesn’t stabilize the heavy, high-BC .22 centerfire bullets as well as the .224 Valkyrie. Also, the case is too long to play nice in AR magazines when loaded with super-long, sleek projectiles. As a result, the 22 Nosler is better with traditional 50- to 77-grain bullets. This fine little cartridge really found its home with passionate predator hunters that wanted more speed and more bullet weight in their AR-15 predator rifles but weren’t interested in super-heavy bullets and 1,000-yard shooting. However, we’re here to compare long-range AR-15 cartridge capability. Let’s take a look at the 22 Nosler when loaded with Nosler’s own 85-grain RDF Match bullets — a relatively sleek, mag-compatible long-range projectile that the cartridge handles very well. This projectile has a G1 BC of .498 and is advertised to exit the muzzle at 2,750 fps in an 18-inch test barrel. That’s the same speed as a common 20-inch 5.56 NATO generates with the 77-grain TMK but adds more bullet weight and has a significantly higher BC. Muzzle energy is 1,427 ft-lbs. In sea-level atmospheric conditions, the 85-grain RDF stays supersonic to nearly 1,050 yards. When zeroed at 200 yards, it drops 358 inches at 1,000 yards and drifts 103 inches in a 10-mph crosswind. Velocity at 1,000 yards is 1,167 fps, and the bullet impacts with 257 ft-lbs of energy. While still an improvement over the 5.56 NATO and legitimately capable to 1,000 yards, it does give up a bit to the .224 Valkyrie simply because of its inability to shoot the super-long, extreme-BC projectiles. Keep in mind, however, that the .224 Valkyrie’s advertised muzzle velocity is from a 24-inch barrel, while the 22 Nosler’s is from an 18 incher. Put them in equal barrel lengths, and the performance gap narrows considerably.

6mm ARC

Although the youngest of the modern AR-15 cartridges listed here, the 6mm ARC is arguably the best for across-the-spectrum performance. Born in 2020, it utilizes the .220 Russian as its parent case, just like the 6.5 Grendel discussed next. It’s optimized to push high-BC, 6mm bullets to useful velocities. Such projectiles hit harder than any .22 centerfire bullet can, thanks to greater weight, frontal diameter, and kinetic energy. That, as a matter of practical fact, is what really makes the 6mm ARC shine. It runs with the best of the long-range .22 centerfires and impacts with more authority. Let’s look at some numbers. The best of the long-range 6mm ARC factory loads is Hornady’s 108-grain ELD Match ammo. This projectile has a G1 BC of .536 and is rated to exit the muzzle of 24-inch barrels at 2,750 fps. Muzzle energy is 1,813 ft-lbs. In sea-level atmospherics, the 108-grain ELD Match stays supersonic to nearly 1,150 yards. When zeroed at 200 yards, it drops 331 inches at 1,000 yards and drifts 89 inches in a 10-mph crosswind. Retained velocity at 1,000 yards is 1,285 fps, and the bullet is carrying 396 ft-lbs of energy. As you can see by studying the numbers, the 6mm ARC’s bullet is right there with the .224 Valkyrie’s, which to this point has posted the best numbers. Drop, in fact, is a bit less. Wind drift is a tad more. Retained energy is more. However, due to the Valkyrie bullet’s slightly higher BC, it stays supersonic about 50 yards further. Data is data, and I’ll let you study it and draw your own conclusions between those two. However, on a practical note, I’ll point out that the 6mm ARC is growing in popularity, while the .224 Valkyrie unfortunately seems to be languishing. The ARC may simply outlive the Valkyrie.

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6.5 Grendel

As the second oldest of the AR-15 cartridges listed here, the 6.5 Grendel is the second most proven. The fact that several companies load factory ammo for it indicates it’s here to stay. Designed in 2003, the Grendel uses the .220 Russian for a parent case and was engineered to give AR-15 shooters more authority. Although originally intended to maximize potential out to 800 yards with a 24-inch barrel and the right projectile, it’s capable past 1,000 yards. There are a couple of good bullet choices. Hornady’s 123-grain ELD Match load at 2,580 fps nearly gets it done, going transonic just shy of the 1,000-yard mark. Federal’s Gold Medal ammo loaded with 130-grain Berger AR Hybrid OTM bullets at 2,400 fps does slightly better. This bullet has a G1 BC of .560, and it stays supersonic to nearly 1,025 yards when fired from a 24-inch barrel. Muzzle energy is 1,670 ft-lbs. Sighted in at 200 yards, the 130-grain AR Hybrid OTM drops 432 inches at 1,000 yards and drifts 100 inches in a 10-mph crosswind. Retained velocity at 1,000 yards is 1,236 fps. Energy is 373 ft-lbs. Compared to the 6mm ARC, which in a way is the 6.5 Grendel’s offspring, the 6.5 Grendel offers a bit more bullet weight and frontal diameter. However, the ARC fires nearly equal or higher-BC bullets significantly faster. This gives the ARC 100 yards more supersonic bullet flight, a whole bunch less bullet drop (101 inches less at 1,000 yards!), and 11-percent less wind drift. Even energy at both the muzzle and at 1,000 yards is more than the 6.5 Grendel provides.

Best of the Best

Again, data is king, and studying the notes and the chart here is revealing. Keep in mind that each of the loads presented features the best long-range projectile I could find for each cartridge, so it represents the pinnacle of potential in each. A few performance notes unrelated to long range: Recoil increases as bullet weight and velocity increase. In ascending order of recoil, the list goes 5.56 NATO, 22 Nosler/.224 Valkyrie (basically identical), 6mm ARC, and 6.5 Grendel. However, even the Grendel’s recoil is so mild that it’s a non-issue for even recoil-sensitive shooters. In terms of availability, 5.56 NATO will always be king. Different magazines are needed for most of the cartridges listed. The 6mm ARC and 6.5 Grendel both use the same type. The 22 Nosler and .224 Valkyrie use the same mags as the 6.8 SPC.

If you use a suppressor, the 22 Nosler and .224 Valkyrie are both compatible with .22-caliber centerfire silencers, same as you’d use for any 5.56 NATO. The 6mm ARC and 6.5 Grendel require suppressors with larger holes through the baffles, so a .30-caliber suppressor is usually most practical. Install a front port reducer for 6mm or 6.5mm for best sound reduction. In practical terms, the 6mm ARC offers the best balance of reach, ballistic capability, and energy at any distance. Plus — and this is subjective — it’s probably the most inherently accurate of them all. In my experience, nearly all 6mm ARC rifles shoot well. Contrastingly, in my experience, most 22 Nosler and .224 Valkyrie rifles need considerable load testing and tuning to shoot with excellent accuracy. Most 5.56 NATO and 6.5 Grendel rifles fall somewhere between. A straight-up comparison of data indicates that the .224 Valkyrie offers the best long-range performance. Its bullets stay supersonic the farthest and drift the least in the wind. Data says it’s top dog. But then, it’s not always about data.