6.5 Grendel vs 5.56: Head-to-Head Comparison
The AR-15 is one of the most popular rifles in the world and the most popular rifle on the American market. The AR-15 was designed around a specific caliber, the 5.56/.223 REM but expanded rapidly into a wide variety of calibers. This includes pistol rounds like 9mm, rimfire rounds like the .22LR, and various different rifle rounds, like the 6.5 Grendel.
That brings us to the subject of today’s article: the 5.56 vs. the 6.5 Grendel. These two rounds have a fair bit in common. They are both intermediate cartridges designed and utilized in the AR platform rifle, and both have steady followings. The 6.5 Grendel has a more cult-like following than the 5.56, with the 5.56 being the uncontested most popular AR cartridge ever created.
Anytime we do a head-to-head comparison, it’s wise to know why we are doing such a comparison. The 5.56 and 6.5 Grendel have a fair bit in common, but they also have a lot of differences. This creates a unique comparison between the two rounds that should be fascinating to explore.
5.56 NATO History
5.56 NATO
An affordable and lightweight modern rifle round that’s best used for plinking and home defense.
Oh boy, we could write a short book on the history of the 5.56 cartridge. The 5.56 NATO is a creation of FN Herstal out of Belgium but is directly tied to the .223 Remington. The U.S. Military conducted a number of different experiments that led them to figure out that a high-velocity, small-caliber cartridge was the way to go.
The development of the .223 Remington and 5.56 are both tied to the development of the small caliber high-velocity rifle concept. The .223 was created in 1964 after two years of experimenting. The 5.56 was a NATO standardization of the .223 Remington, which made some notable changes. The 5.56 NATO became NATO’s second rifle caliber in 1980, but it was created and developed in the 1970s.
The 5.56 NATO remains the standard cartridge of NATO and the United States military. It’s also the most common AR cartridge on the market. If you buy your first AR, it will likely be a 5.56 rifle.
6.5 Grendel history
The 6.5 Grendel doesn’t have the same long and rich history of battles won and wars fought. The 6.5 Grendel came to be in 2003, so it’s old enough to buy a beer. Bill Alexander, Arne Brennan, and Janne Pohjoispää designed the 6.5 Grendel specifically for the Armalite platform and designed it as a low recoil, high precision intermediate cartridge.
The round premiered in 2003 at the old Blackwater Facility to great fanfare. The cartridge proved to be quite the performer in an AR platform rifle. In this era, there was a big rush to try and replace the 5.56 round, which spawned numerous calibers vying for that position, including the 6.5 Grendel.
The cartridge didn’t unseat the 5.56 NATO round, but it provided an alternative that seemingly offered outstanding performance from a lightweight, low-recoiling rifle platform. The round has expanded out of the AR into various platforms. In terms of military adoption, the Serbian armed forces have adopted the cartridge, and the French GIGN have also adopted the round.
Accuracy and Ballistics
As an intermediate cartridge, the 5.56 excels within 300 yards. That’s where you see it’s best performance. The round still does well out to 500 yards, and in the right rifle, with the right shooter does well even beyond those ranges. If you’re reaching out beyond 500 yards, you need something beyond a bare-bones AR to get it done.
At those 500 to 600-yard ranges, the round does start to lose energy and is easily subject to wind pushing your round off track. Lightweight rounds do that.
The 6.5 Grendel was built to excel at both intermediate and longer ranges. In range and performance, it’s best to think of the 6.5 Grendel as a cartridge between the 55.6 and 7.62 NATO rounds. The 6.5 Grendel is at home out to 800 yards. Of course, it does require an 800-yard shooter, but if we eliminate human and mechanical error, the 6.5 can reach out there and touch something.
The 6.5 Grendel can also get out to 1,000 yards, but again, that requires a good rifle, shooter, and ammo. That’s a lot of range from an AR-15. More than range, you are getting more energy and better penetration at every range. The heavier bullets tend to resist wind, and the 6.5 projectiles also have an excellent ballistic coefficient.
The 6.5 Grendel outperforms the 5.56 NATO in accuracy, range, and ballistics. This is emphasized even more when you consider both rounds are fired from the same rifle. One popular genre of modern AR-15 is the SBR or AR pistol. Short barrels are so hot these days.
Can the 5.56 outperform the 6.5 Grendel when we trim the barrel? No, not really. The 6.5 Grendel still goes further and hits harder. If we get into those ultra-short territories, the performance likely starts to shrink, but the 6.5 Grendel will have a consistent edge over the 5.56.
Recoil
The 6.5 Grendel is a bigger, heavier bullet that moves quite fast and goes quite far. As they say, there is no free lunch, and the price you pay comes down to recoil. How much recoil? If we compare the cartridge to the 5.56 from a rifle of the same weight, we can expect about twice the recoil impulse.
The 6.5 Grendel hits you twice as hard as 5.56. That’s notable and will affect your ability to shoot quickly and accurately. That said, twice the recoil of 5.56 still isn’t much. You aren’t moving up into 12 gauge shotgun territory or anything similar. It’s not going to beat you up and leave you bruised and beaten.
The 5.56 and its lighter recoil make it an outstanding close-range cartridge. Less recoil means less movement, and less movement makes a gun easier to shoot faster with a greater degree of accuracy. Up close, the 5.56 has advantages, especially for home defense and similar roles.
Logistics and Cost
Predictably, the 5.56 takes a massive lead over the 6.5 Grendel regarding logistics. When we discuss logistics, we are talking about firearm and ammo availability, magazines, muzzle devices, and all the other support gear that helps you get on target with your chosen caliber.
You have plenty of AR options in 6.5 Grendel, including budget options, and a few other rifles have chambered the cartridge. You’ll be able to get into 6.5 Grendel easily enough, especially with the wide world of the internet.
The 5.56 is a different beast. You can find any type of rifle and even handguns in the cartridge. We can get anything in 5.56 or .223 Remington. In the AR world, there are tons of magazines, different rifles, optics, suppressors, and more. The 5.56 gives you way more options in ammo, rifles, and more.
Not only will 5.56 give you more options, but it will also give you more affordable options. The cartridge’s commonality makes it much cheaper to purchase. It’s radically more affordable than the 6.5 Grendel. The cheapest 6.5 Grendel I can find is about a dollar a round. With 5.56, you can find the cartridge for less than 50 cents a round.
That’s a massive difference and one we have to note.
What the 5.56 Excels At
If you want an affordable intermediate cartridge that can hunt medium—to predator-sized game, the 5.56 round is the better option. It has very low recoil and is very affordable. The 5.56 round is also the better option for home defense, general plinking, competition, and similar situations. If you want the most customization and commonality possible, the 5.56 round is the cartridge to go with.
What the 6.5 Grendel Excels At
The 6.5 Grendel allows you to reach out and touch a target from a moderate-sized, lightweight rifle. The 6.5 Grendel cartridge excels at its purpose of being an accurate, long-range round that can be fired from a very light and, most importantly, semi-auto rifle. The 6.5 Grendel is better suited for hunting medium game and making long-range shots.
In The Real World
The 5.56 remains one of the most popular rounds ever created and will likely maintain its popularity for the near future. The 6.5 Grendel is theoretically the better cartridge, but it comes at the cost of increased recoil and a much higher cost of entry. Both rounds offer distinct advantages, and the end user will need to determine their needs above all else.
About Travis Pike
Travis Pike is a former Marine Machine Gunner and a lifelong firearms enthusiast. Now that his days of working a 240B like Charlie Parker on the sax are over, he's a regular guy who likes to shoot, write, and find ways to combine the two. He is a "simplicisist" when it comes to talking about himself in the 3rd person and a self-professed tactical hipster. Hit him up on Instagram with story ideas.
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