If you hit up any weapons forum with a question concerning which round is preferred, the 6.5 Grendel vs 300 Blackout in an AR build – you are asking for a firestorm of opinions. Both of these rounds are popular for their own reasons, but controversy surrounds whether the 6.5 Grendel will truly ever get the platform many feel it deserves due to being pushed into a niche market.
Although the 300 BLK offers quite a few more options, especially concerning suppressed subsonic loads- trying to compare the two is like offering up apples to oranges. Now that I’ve probably triggered a few people (pun intended), let’s get down to the basic specs and ballistics of these two rounds so you can decide which might be best for your shooting needs.
What’s The Difference Between 6.5 Grendel vs 300 BLK Rounds?
In terms of affordability, trajectory, and shooting distance, the 6.5 Grendel far outperforms the 300 Blackout, but you have to ask if it is even a fair comparison since the rounds are designed for specific intended use- although both can get the job done as a hunting round within a set distance.
Comparison Between 6.5 Grendel and 300 BLK Rounds
Taking a look at the basic ballistic of these two in a side by side comparison highlights exactly why they are in very different arenas from one another. Each provides a truly powerful option, but are built for different firing capacities, and only one has an easy, and simple AR modification platform that won’t break the bank. Take a look at the details of this below.
Comparison Table
Features
6.5 Grendel
Brand
Speer TNT (90 gr)
AAC (125 gr)
Bullet Size
Bullet Size: 2.26 inches
Bullet Diameter: 0.264 inches
Shell Case Length: 1.52 inches
Bullet Size: 2.26 inches
Bullet Diameter: 0.308 inches
Shell Case Length: 1.368 inches
Energy (per 200 yards)
1,383 ft-lbs
824 ft⋅lbf
Velocity (per 200 yards)
2,278 ft/s
1872 ft/s
Muzzle Energy/Velocity:
1658 / 2880
1360 / 2215
6.5 Grendel
Brand
Speer TNT (90 gr)
Bullet Size
Bullet Size: 2.26 inches
Bullet Diameter: 0.264 inches
Shell Case Length: 1.52 inches
Energy (per 200 yards)
1,383 ft-lbs
Velocity (per 200 yards)
2,278 ft/s
Muzzle Energy/Velocity:
1658 / 2880
300 Blackout
Brand
AAC (125 gr)
Bullet Size
Bullet Size: 2.26 inches
Bullet Diameter: 0.308 inches
Shell Case Length: 1.368 inches
Energy (per 200 yards)
824 ft⋅lbf
Velocity (per 200 yards)
1872 ft/s
Muzzle Energy/Velocity:
1360 / 2215
6.5 Grendel
Introduced in 2004, the 6.5 Grendel was designed to outshoot the popular 5.56mm NATO/.223 Remington cartridge and provide amazing accuracy with a lower recoil. The shorter, larger diameter case was made to hold more powder volume, and offers factory load ammunition ranging from 9-0 to 130 grains in weight for a very versatile shooting experience.
Features
The design of this cartridge creates a flat trajectory and longer projectile, making it accurate at much longer distances compared to its predecessors. It is very similar to the .220 Russian case, but larger than the 5.56×45mm NATO, so your AR modification needs to include a non-standard AR-15 bolt upgrade. It is most popular as a powerful hunting round for deer or other big game, especially when long-distance, lethal rounds are in need.
Pros
The 6.5 Grendel outperforms just about anything it is put up against, as it is built to do. It is an affordable option both for hunting and as a competitive round, and provides a deep penetrating option that can maintain supersonic speeds for a longer time. In short, the energy is hard to surpass as our chart shows. The high ballistic coefficient makes it a favorite, plus the recoil is incredibly reduced, allowing you to shoot longer in comfort.
Cons
Despite the popularity and bullet affordability, if you plan on converting your AR to handle the round, it isn’t going to be cheap. Unlike the 300 BLK, you need to replace more than just the barrel. As mentioned, you will need a bolt upgrade, and finding a suitable magazine isn’t as simple as loading your reliable 5.56 mags – since the sizing is not comparable. Together, these modifications are partially one reason why the 6.5 Grendel hasn’t surpassed the 300 BLK in overall availability despite how long they have been around: they simply cost a lot.
300 Blackout
The 300 BLK rifle and pistol configurations are a popular pick for firearm enthusiasts. Created for close range combat, they are a great option for both home defense as well and hunting. More recently introduced than the 6.5 Grendel, they made their way into the industry in 2011 and become popular due to the affordability, accurate range, and excellent power.
Features
Originally modified from the 5.56 NATO, it was designed to allow easy AR-style rifle modification with a simple barrel change. It is a budget friendly choice that is reloader friendly, and fits well within existing AR platform magazines- which is one less purchase you would need to make. It also provides great long range shooting accuracy and awesome energy, however, it will max out at about 500 yard even with the proper gas system- while the Grendel will be accurate between 800 and 1000 yards in the correct build.
Pros
The easy AR platform makes it a very popular choice since it is an affordable and easy DIY modification. The Blackout round is a bit heavier than the Grendel, giving it more initial energy, and making it a lethal hunting option that has been popular for almost a decade. It also outperforms many competitive rounds due to its lighter, and overall smaller size.
Cons
There truly isn’t much that can be said against the .300 BLK. It is popular and affordable, and provides something new and different for firearm enthusiasts without having to initially spend a whole lot. One thing to make note of, suppressed subsonic loads are considered the superior way to shoot for maximized potential. However, it isn’t a deal breaker for those who know its full potential.
Stand Out Features
Mentioned early on, I made the comment that these two rounds are like comparing apples and oranges, and they are. Both are excellent choices for hunting, both have awesome stopping power and energy, and both are accurate and dependable. Although when the ballistics are compared side by slide, the 6.5 Grendel looks as if it stomps all over the 300 BLK- you have to consider the design of each and understand the details that are going into shooting either round.
In terms of distance and velocity, the Grendel is the clear ‘winner’, but that doesn’t always mean it is better. It just means it is a quality option- as is the Blackout option. For close range shooting, you definitely may want to stick with the tried and true 300 BLK, but for distance competition and open range hunting, the Grendel is the better choice.
Conclusion
All you need to convert an existing AR style rifle to accept the 300 BLK is a new barrel, while conversion for the 6.5 Grendel is going to take a bit more time, effort, and cash if you choose not to purchase a 6.5 set-up. The fact that it has been around for close to 2 decades and still does not have a huge array of options for shooting also speaks to the fact that it isn’t likely the platform will become much more popular than it already is, and will continue to fill the unique niche it has grown into.
The 300 BLK already has a huge platform with a variety of build options in both pistol and rifle options, and with plenty of modification materials at the ready for your own DIY upgrades.
They both are truly incredible rounds, however, and truly your choice has to be a personal one (if you have to make a choice).
6.5 Grendel Overview
- Incredible energy and efficiency
- Excellent range of weights for various ballistic needs
- Less recoil
- Great for long range targets with very little loss of trajectory
300 BLK Overview
- Accurate, efficient, and dependable
- Compatible with existing AR mags
- Easy to modify existing AR platforms
- Good trajectory past 200 yards, but amazing for close range shooting scenarios
If you’ve had a chance to shoot either round, we’d love to hear about your experiences below- and what detail you feel should be mentioned that we may have missed. And, as always, please share!