6.5 Grendel vs 6.8 SPC: Which Has Better Ballistics

The world of cartridges has many debates and battles. We have seen many people trying to brag that one cartridge is better than the other. Of course, these are just regular instances. If you can't get used them, you will never know the real capacity of every unit in the market today.


Among the most contested parleys, today is the 6.5 Grendel vs. 6.8 SPC. Now, don't get us wrong. We have no interest in taking sides here. That won't benefit anyone. Instead, what we want to do here is to highlight the features, advantages, and disadvantages of these two cartridges. By doing this, you will be able to discern which one of them will fit your intended needs and applications.

So if you are ready to know the nuances between the 6.5 Grendel and 6.8 SPC, you better go through this article. We have prepared a blow-by-blow account to compare these two fantastic cartridges for AR-15.

6.5 Grendel Vs. 6.8 SPC: A Preview

Bullet “A” is the 6.5 Grendel. Bullet “B” is the 6.8 SPC

Both of the 6.8 SPC and 6.5 Grendel made it on the market without meeting the correct chamber size and dimension. Gradually, their manufacturers corrected this error. The subsequent modifications enable the cartridges to get a 100 to 200 FPS boost on their velocity.

Many think that the existence of the 6.8 SPCII chamber makes the 6.8 SPC the better choice. However, you should realize that the Grendel II is already out on the market today. Of course, the latter is a product of several upgrades from its first version.

For reloaders out there, these particular pieces of information are all they need. For the rest of non-reloaders (like us and probably you), resorting to factory ammo is the best option.

6.5 Grendel: An Introduction

First introduced in 2004, the 6.5 Grendel has no qualms when it comes to engineering, design, and innovation. This particular cartridge excels on long-range shooting and military applications. It somehow amplified the capacity of AR-15 rifles upon its arrival.

This particular cartridge is quite versatile. It can work for light bullets for varmint hunting under the 90-grain category. The latter is extremely accurate for small games, by the way. It could also be shifted towards 108-grain to 120-grain bullets for standard shooting competitions. In fact, others use this as a 130-grain or 140-grain bullet for tactical and long range applications.

There were a lot of modifications that the 6.5 Grendel received before it achieved its form today. The final design improved the internal load of the cartridge through shifting the position of the shoulder. Moreover, the thickness of the shoulder and neck of this cartridge are durable so that the case can work with high-powered semi-automatic rifles. Of course, it is also noticeable that the external taper of the case was modified, too.

The 6.5 Grendel is capable of out-shooting a 7.62 NATO. It can still display its supersonic speed even at 1,200 yards, delivering a flawless ballistics. When used with AR-15, the terminal and external ballistics and accuracy of this cartridge are fully displayed. If you compare it to 5.56 NATO, the 6.5 Grendel has almost double lead mass. Therefore, if the highest fragmentation output coincides with the largest temporary cavity, the 6.5 Grendel will have an exceptional terminal ballistic.

In application, the 6.5 Grendel is ideal for tackling tough games such as hogs and deer. It can also work for tactical and military shootouts. After all, it has the power and needs to demolish any target that it hits.

6.8 SPC: An Introduction

The flexibility of the AR system practically gave birth to the 6.8 SPC. This particular cartridge was created by some top brass individuals from U.S. Army Marksmanship Unit to replace the 5.56mm cartridge. Just a quick note: the 6.8 SPC only has a partial compatibility on AR units.

Specifically, the 6.8 SPC is a response to the obvious downsides that are present in the 5.56mm cartridge. The stopping power of the 5.56mm is an issue, especially when paired with short rifles. Meanwhile, the 6.8 SPC has a significant leverage when it comes to this aspect, even with .308 cartridges. Despite this, the capacity of the 6.8 SPC does not follow reduction due to the size and weight of its case.

You can get a clear distinction between the 6.8 SPC and 5.56mm if you put them on the test. Try firing 25 rounds for each of these cartridges. After firing, you will realize that the 6.8 SPC has better ballistics and speed over its predecessor.

It is notable that 6.8 SPC is comparable to other common cartridges on the market today. One good example for this is the 150-grain .308 Winchester Magnum. The latter has a 2,850fps and a recoil of 2,704 pounds. Another similar cartridge that you can compare the power of the 6.8 SPC is the .30-30 win mag. This 150-grain cartridge has a 2,300 fps with a record of 1,761 pounds.

The number of compatible magazines to the 6.8SPC is just limited. Only those dedicated manufacturers were able to produce magazines that can cater this cartridge. These magazines have excellent spacing and reliability, which ideal for long cartridges such as the 6.8 SPC.

One of the selling points of the 6.8 SPC is its insane speed. Specifically, its terminal speed on down range application is faster than any AK-47 rounds by 200FPS.

6.5 Grendel Vs. 6.8 SPC: A Comparison

Now that we know the basics of these two cartridges, we will now compare their capabilities. Let's gets started!

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    When it comes sectional density, the 6.5 Grendel brings home the bacon. There is no denying that the 6.8 mm is larger than the 6.5 mm bullet. You can't fool anyone about that. Specifically, the sectional density of the 6.5 Grendel can reach up to .264. The higher the sectional density, the better aerodynamics of the bullet.
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    Notably, both of these cartridges don't do well with heavy bullets. The balls tend to stick far on their cases. Take note that substantial parts are long. As a result, they can only contain few gunpowders. In application, that only means that these bullets have slow velocities.
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    Additionally, the 6.5 Grendel has a healthy balance between bullet weight and velocity. You can achieve this feat within the 100 to 123 grains. Meanwhile, the 6.8 gets this optimal state at 100 to the 120-grain category. The 6.5 Grendel can accommodate a 123-grain bullet, achieving a sectional density of .252. On the flipside, the highest that the 6.8 SPC can cater is a 120-grain bullet (.223 sectional density). As we mentioned, cartridges with high sectional densities have excellent aerodynamics.
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    Because of this slight discrepancy, the 6.5 Grendel has better trajectories compared to the 6.8 SPC. When fired with the use of a Hornady bullet, the 120-grain SPC will start 100 fps quicker than the 123-grain 6.5 Grendel. Upon reaching 250 yards, both of the cartridges are almost the same. But on the 500 yards, the speed of the 6.5 Grendel is still maintained, causing it to have a 100 FPS lead over the 6.8 SPC. If you increase the length of the barrel, the 6.8 SPC will surely get outclassed
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    It is also worthy to highlight that the 6.8 SPC doesn't get too much speed if used with a 16-inch barrel or longer. Some will call it as an advantage. Some would deem this is a drawback. The perk of this predicament is that it highlights the quality of the 6.8 SPC on not-so-lengthy barrels. But on the other hand, it directly tells you that this cartridge is not flexible when it comes to this aspect.
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    When it comes to hunting, both of these cartridges have the same lethality. If you have proper placement, any of these cartridges can take down large games in a single hit. The only things that they differ are the velocity and the range. The 6.5 Grendel drops gradually and remains unfazed even against the wind. That means that your accuracy is preserved even in great distances.
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    Lastly, we want to emphasize that the 6.8 SPC is way more expensive than the 6.5 Grendel. Moreover, the $0.30 Grendel has better value, too. After all, the Grendel follows the military specs. Today, the cheapest 6.8 SPC cartridge that you can get is around $70 per round. Sadly, this is just the basic model, which is only great for practice and not for the real thing.

Final Verdict

With their capacities placed side-by-side, it is notable that the 6.5 Grendel has slightly better speed, trajectory, and reach than the 6.8 SPC. You may diminish these minor discrepancies once you take them on the field already.

They possess the same power and lethality, hence making excellent cartridges for many AR-15 hunting rifles. But if the condition is windy, the accuracy of the 6.8 SPC deteriorates slightly, especially when it reaches the 500-yard mark.

But overall, these two cartridges are still durable, and they are performing well. You can enjoy their reliability and power, especially on large game hunting. They also suit tactical applications, too.

However, always remember that your performance lies on the type of cartridge that you are using. It will always be you that can change the game. If you want to get accurate and clean kill shots, better focus on practicing rather than arguing on the internet. In this way, you can maximize the potential of your gears, which in turn, will justify the investment you poured to them.

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