Here we will compare the 6.8 SPC and 6.5 Grendel cartridges, explaining the pros and cons of each to help you make an informed decision on what round your want to use and for what type of shooting.
It’s important to note that the .223 Remington and 5.56x45mm NATO cartridges do not perform identically. The 5.56x45mm NATO cartridge has higher pressure than the .223 Remington, so it is not safe to fire 5.56x45mm NATO ammunition in a firearm chambered for .223 Remington.
History Of The 6.5 Grendel & 6.8 SPC
The AR-15 rifle and .223 Remington cartridge have a long history.
The M-16 rifle, the military version of the AR-15, and the 5.56x45mm NATO cartridge were used in Vietnam by the U.S. military but had some issues. Despite changes made to the rifle and ammunition, some people in the military still had doubts about its ability to stop an enemy effectively.
Civilians also had concerns about the effectiveness of the AR-15 and .223 Remington cartridge for hunting larger game. The .223 Remington was known for not being effective on deer-sized game, but it worked well for target shooting, hunting predators, and small game.
The AR-15 rifle was designed to be a lightweight and easy-to-use weapon. It quickly gained popularity among shooters in the United States because of its ease of use and availability.
Gun designers realized they could make money by catering to the American hunting and shooting communities. Since many people loved the AR-15, designers created several larger bore cartridges that were more powerful than the .223 Remington but would still fit in AR-15 rifles.
This list contains cartridges such as the Win .308, .300 Blackout, the .450 Bushmaster, the .458 SOCOM, 9mm, and the .50 Beowulf.
In 2002, Bill Alexander, who also developed the .50 Beowulf, designed the 6.5 Grendel to address this issue. Alexander successfully modified a 6.5mm PPC case to build an efficient, accurate, sweet-shooting cartridge that functioned well in the AR-15 platform.
The 6.5 Grendel is a more powerful cartridge than the .223 Remington. This cartridge is suitable for many types of shooting, including shooting from far away, hunting small animals, and hunting large animals.
The cartridge was not popular initially because Bill Alexander trademarked the name, among other reasons. Alexander relinquished the trademark to the 6.5 Grendel cartridges in 2011 when it gained approval from SAAMI (Sporting Arms and Ammunition Manufacturers’ Institute), thus allowing other companies to manufacture products related to the 6.5 Grendel.
As Alexander developed the 6.5 Grendel, the United States Army Special Forces community asked the Remington Arms Company to help them create an alternative to the 5.56x45mm NATO cartridge. But could still be used in the M-4 carbine.
The 6.8mm Remington Special Purpose Cartridge was developed due to this research.
The people at Remington made a shortened .30 Remington case related to the .32 Remington and .35 Remington. They used this to shoot a 6.8mm (.270 caliber) bullet. The originally intended 115-grain bullet was supposed to travel at 2,800 feet per second, with 2,002 foot-pounds of energy.
The gun fired a 115-grain bullet at 2,625 feet per second, offering substantial power.
The 6.8 Remington SPC received SAAMI approval in 2004.
The 6.8 SPC cartridge was more powerful than the 5.56x45mm cartridge, with approximately 40% more muzzle energy than the standard M855 load that the military was using.
The 6.8 SPC cartridge became more lethal than the 5.56x45mm cartridge when both were compared using a shorter 16″ barrel.
In this case, the initial 6.8 SPC rifles had poor chamber designs, which led to pressure spikes when using original factory loads. As a result, Remington downloaded the cartridge to keep pressures at safe levels.
Remington fixed the issues with the original SAAMI specification design by adding a .050″ freebore to the 6.8 SPC II chamber. This gives shooters more flexibility when it comes to ammunition choices.
This only happened once the SAAMI approved the cartridge using the older specifications.
The SAAMI specifications of the 6.8 SPC still reflect the old chamber dimensions. Hence, most 6.8 SPC factory ammo options are safe to shoot in rifles with the original dimensions.
The factory loads are safe to use with either a SAAMI 6.8 SPC chamber or a 6.8 SPC II chamber, but the ballistic performance is not ideal.
On the other hand, 6.8 SPC II chambers can safely handle hotter loads. Handloaders with a rifle with a 6.8 SPC II chamber can make custom loads more closely approaching the cartridge’s full potential.
The 6.8 SPC has several advantages, but sportsman do not commonly use it.
Which is Best For You?
I’ve been researching these calibers for a few years. I’ve read a lot to try to figure out what the best “all-purpose” AR-15 caliber would be. I consider several factors when I say a particular gun is suitable for use. Its usefulness for hunting animals of different sizes, its accuracy and penetration for long-range target practice and hunting, and its power for close-quarters combat or self-defense.
Additionally, I consider the cost of each round and the gun’s overall effectiveness.
Many articles are based on emotion and personal taste rather than facts and ballistics. This article aims to present the information the author sought several years ago before they spent money on A.R. uppers. This information may be helpful to other people who are considering purchasing A.R. uppers in the future. I have five different A.R.s in different calibers, and I love almost all of them. I was looking for just one upper several years ago to meet my many needs, and I know many other people looking for the same thing.
Some people compare the AR-15 to the AR-10 (.308), even though the AR-10 is a better rifle. I’ve compared many manufacturers of these three rounds of various bullet weights.
They have all been fairly consistent. I chose to use Hornady because they have a good reputation, and I have had good experiences with them. I got the ballistics from Nikon’s “Spot-On Ballistics Match Technology.” I also looked at the ballistics of Hornady but only had information going out 500 yards. It remained consistent with other info I have seen. I always say, “the proof is in the pudding .” Pay attention to the ballistics and note the ballistic coefficient (B.C.) for each one.
6.8 SPC 120 gr Hornady SST can be found for as low as $0.86 per round. While the cheapest (Remington) can be found for $0.79 per round.
Test Barrel (16″) Velocity (fps) / Energy (ft-lbs)
MUZZLE 100 200 300 400 500
2460/1612 2250/1349 2050/1120 1862/923 1685/756 1522/617
The Grendel rifle uses 6.5 gr Hornady A-max bullets, which can be found for as low as $.88 per round. The cheapest way to buy these bullets is in bulk from WolfGold for $.62 per round.
Rifle (16″ Barrel) Velocity (fps) / Energy (ft-lbs)
MUZZLE 100 200 300 400 500
2350/1508 2189/1308 2034/1129 1885/971 1744/831 1612/709
.308 cartridges that weigh 155 grains and are made by Hornady can be found for as little as $1.04 per round.
Test Barrel (24″) Velocity (fps) / Energy (ft-lbs)
MUZZLE 100 200 300 400 500
2850/2795 2639/2397 2438/2045 2245/1735 2062/1463 1887/1225
I would have to say it’s a “no-brainer.” The 6.5 Grendel will be better than the 6.8 SPC in most ways. Than the .223 I have seen arguments that suggest the 6.8 SPC is a better close-quarters combat round than the .223. I get upset when I read that the 6.8 will outperform the 6.5 under 300 yards and that the 6.5 is better for long-range hunting while the 6.8 has more knockdown power. Why is kinetic almost the same from muzzle to around 300 yards with the same weight bullet?
The difference is so insignificant it doesn’t matter. There is little difference in accuracy at long range between the two calibers. Most people agree that the 6.5 caliber has a slightly higher accuracy due to its better ballistic coefficient. After traveling 300 yards, the 6.5 model outperforms the other models’ speed and accuracy. So 0-300 yards, they are relatively equal. When looking at objects from a distance of 500-1000 yards, there is no way to compare them. Why would you not want a gun that can shoot both short and long-range? The 6.5 Grendel and the .308 have very similar ballistics at 1000 yards. The 6.5 caliber bullet is slightly faster than the average bullet but has less energy due to its lighter weight. The 6.5’s sectional density is much higher than the .308’s, so it can better penetrate targets. I’m only comparing a 6.5 to a .308 at a “long” distance.
There is little difference in speed and energy less than 500 yards. The .308 is a far superior choice if you stay under 500 yards.
It has been said that the 6.8 outperforms the 6.5 even when using a shorter barrel. Hornady’s 6.8 SPC 120 gr SST and 6.5 Grendel 123 gr A-max are great options when you need a heavy-hitting bullet. The 6.5mm bullet outperforms the 5.56mm bullet in speed and energy when fired from a 16″ barrel at targets up to 300 yards away.
What about the cost? I have read many articles that suggest the 6.8 is a better choice than the 6.5 due to its cost. More companies make the 6.8 cartridges, but it is usually cheaper to buy the 6.5. You can check the prices on ammoseek.com. I purchased 500 rounds of WolfGold MPT for $12.50 per box of 20 rounds. That is pretty cheap! Some people say Wolf will start providing steel-cased ammunition in 6.5 caliber sometime soon. Now that A.A. has released the trademark for the 6.5 Grendel, it’s only a matter of time before more companies start making products of this caliber. This has been “not so attractive” in the past because of royalties. I have only found ammo for the 6.5 in 2-3 manufacturers. I hope people will realize this caliber’s true capabilities and reality. The cost per/rd from Hornady is about the same. Cheaper than match ammo.
There is a large selection of 6.5s if you are interested in reloading. Hornady has a variety of 14 different choices of bullets, ranging from 95 grain to 160 grain. There are 14 other 6.8s, depending on whether you want a .277 or a 270. The two choices have a lot of variety for reloading, but the 6.8 SPC currently has more ammunition options.
I would evaluate the three based on the following:
- CQC: How well the weapon works in close-quarters combat
- Combat/self-defense: How well the weapon works in combat or self-defense
- Hunting: How well the weapon works for hunting
- Target shooting: How well the weapon works for target shooting at both short and long-range
- Weight of ammunition and rifle: How much ammunition and the weight of the rifle
- Cost for shooting: How much it costs to shoot the weapon
The 6.5 Grendel wins without a second thought.
Why hadn’t the 6.5 been more embraced by the civilian population for years? Some people wanted you to think the cartridge could have been better than the others. The legal aspects surrounding the name/trademark “6.5 Grendel” were problematic. An issue with trademarks, legalities, and royalties prevented most mainstream A.R. companies from producing a great cartridge.
The good news is that SAAMI have accepted the 6.5 Grendel and that Alexander Arms has agreed to release their trademark “6.5mm Grendel.” This means other manufacturers can now produce ammunition and firearms chambered for the 6.5mm Grendel cartridge. In the following year, there should be a significant increase in companies manufacturing firearms and ammunition in the 6.5 caliber.
I hope that the military will now reconsider this cartridge for NATO.
Captain Hunter is a seasoned hunting mentor with over 20 years of experience in the field. His passion began as a young man on trips with his father and grandfather in the Colorado mountains. Today, he shares his unmatched skills in survival, tracking, and marksmanship through his website CaptainHunter.com. When he's not volunteering with youth hunting programs, you can find Captain Hunter providing expert hunting tips, gear reviews, and answers to your most pressing questions. His decades of experience make him the trusted guide to help any outdoorsman master the sport.