The .300 Blackout, also known as .300 AAC Blackout, .300 BLK, and 7.62x35mm, fires a much stouter, larger round than 5.56 and .223, which have reigned supreme in the world of AR builds since time immemorial.
That begs the question, when you can so easily find 5.56 ammo and rifles chambered in it are a dime a dozen, why would you put extra effort (and money) into a .300 Blackout build kit?
Let’s take a look at just a few of the reasons why.
Improved Stopping Power
First things first, if you look at a .300 Blackout round, you will see just how much of a difference there is between the bullets it fires as compared to a 5.56.
This cartridge commonly fires bullets between 75 and more than 200 grains. By contrast, a 5.56 bullet that weighs more than 70 grains is getting toward the heavy end.
As a significant consequence, the .300 Blackout cartridge offers significantly higher stopping power as compared to 5.56 and .223, especially at intermediate ranges.
This makes it a better cartridge for defensive applications, especially at close ranges, as long as you take into account there is a higher risk of overpenetration given the heavier bullet.
It also means that the .300 BLK offers superior firepower for intermediate game. There are some that would argue that 5.56 and .223 are too light for deer, but few who would say the same about .300 BLK.
Also, for what it’s worth, despite the cartridge’s somewhat limited range it is perfectly accurate within 100 yards, and frankly serviceable out to 200 and perhaps a little farther.
Better with Shorter Barrels
On top of the fact that a .300 Blackout build kit will yield a rifle that will produce superior firepower at close ranges, this cartridge is notable for its ability to allow propellant to fully deflagrate before the bullet leaves the barrel.
This makes it uniquely suitable for builds with short barrels - even those that qualify as SBRs. This, in turn, makes the cartridge perfect for SBRs, AR pistols, and other carbine-length platforms intended for use in close quarters.
The problem with other cartridges that don’t offer the same levels of deflagration is that they produce a lot of fouling and muzzle pop, without imparting the full ballistic potential to the bullet.
To achieve the same performance with 5.56 or .223, you need a barrel that is at least twice as long. That makes this an ideal cartridge for shorter barrels.
.300 Blackout Works Great with Suppressors
If you’re thinking about adding attachments to your rifle, considering the exceptional performance of .300 BLK with short barrels, this is a great opportunity to talk about suppressors.
Since the cartridge allows full to near-full deflagration even with shorter barrels, it is an excellent cartridge to suppress.
Moreover, adding a suppressor won’t just seriously limit the volume of the gun when you pull the trigger, it’ll also have a pronounced impact on recoil and muzzle flip.
In fact, with a suitable suppressor, you can drop recoil quite a bit.
Also, it’s worth a note that since suppressors are NFA items, if you’re worried you can’t get one, you can always opt for a compensator, which will effectively offer the same benefits.
It Offers Considerable Benefits to Reloaders
You might expect a bigger cartridge like this to require a larger propellant load than .223 and 5.56, but it actually requires less, so that’s an economical benefit as well.
What’s even better than this is that you can use 5.56 casings to load your own .300 BLK - you just need to trim down and neck out the casings - and make sure they’re in good shape.
All in all, if you’re a 5.56 shooter and have a lot of brass around, you might be able to work with what you already have. In fact, instead of getting a whole .300 Blackout build kit, you might be able to swap out your upper to convert the rifle.
What Else You Need to Know About .300 Blackout
While it is true that there is a large list of summary benefits associated with .300 Blackout as a cartridge and by extension to builds crafted around it, it’s not all positive. There are a few things you should know about the cartridge going into this.
First, the cartridge itself is harder to find and a lot more expensive than both 5.56 and .223. Also, it offers abysmal performance at longer ranges. It’s effective out to say, 300 yards, but performs poorly beyond 100 because of bullet drop.
Also, while .300 BLK can be a very effective defensive cartridge, there’s also a serious risk of overpenetration, especially in close quarters - so if that’s a concern for you you might want to go with a lighter alternative.
Explore .300 Blackout Build Kits Here
If you’re in the market for a .300 Blackout build kit you’re in the right place. Shop our full collection of AR build kits and parts and get in touch with us at Sales@MCSGearup.com for more information.