5.56 NATO, 300 BLK, 300 BLK, 7.62x39 Soviet, .308 Win, 8mm Mauser

The 300 AAC Blackout Round

We may earn a commission when you purchase through the links on our site. Find out more here.

The AR-15 has more cartridges than you can shake a stick at and one of the most popular is the 300 AAC Blackout (or 300 BLK for short)!

This .30 cal round is great at supersonic speeds but quiet as a mouse fart when subsonic and suppressed.

From uppers to rifles to ammo, we have all the info you’ll need to kit out your best 300 Blackout!

BONUS OFFER: Get your free shooting range targets to print at home!

Get your free targets to print at home!

Subscribe to our newsletter and get gun deals, educational content, hand's on reviews and news on law changes!

300 AAC Blackout’s History And Origin

Like many cartridges for the AR-15 platform, 300 AAC Blackout came about because of a military need for a better cartridge to do quiet, sneaky stuff with.

While 5.56 NATO is a great cartridge, much of that performance is based on the velocity it travels. Using subsonic 5.56 just makes for a really weak hitter.

What does do well at low speed are 30 cal cartridges like 7.62×39 Soviet. The problem is that 7.62×39 just doesn’t do well in an AR-15 style rifle. 

To really solve all of the issues, they needed a cartridge that had high durability in an M4 style rifle, could be shot both super- and subsonic, was compatible with as many standard M4/M16/AR-15 parts as possible, and kept the full 30-round standard capacity of a STANAG magazine.

5.56 nato and 300 BLK

The result was Robert Silvers of AAC developing the 300 BLK based off of the 300-221 wildcat with some influence of 300 Whisper thrown in.

Practical Applications For 300 BLK


To me, this is where 300 BLK can really set itself apart from other calibers. Perfect for making wild boar dead boar, 300 BLK is a heavy hitter at close range and will help put down threats that 5.56 NATO might have poked a hole in.

5.56 NATO, 300 BLK, 300 BLK, 7.62x39 Soviet, .308 Win, 8mm Mauser
(left to right) 5.56 NATO, 300 BLK, 300 BLK, 7.62×39 Soviet, .308 Win, 8mm Mauser

It’s also just a flat-out better round for larger game like deer than 5.56 NATO is. But, keep in mind that your range is fairly short.

Personal Defense

5.56 NATO is great in home defense. It sounds weird, but 5.56 NATO actually has pretty low barrier penetration compared to many other options like 00 Buck and 9mm.

But a subsonic 300 BLK round is even better. 

With a lot of punch and not much risk of overpenetration, a quality 300 BLK round can be devastating.

Speer Gold Dot 150gr 300 BLK
Speer Gold Dot 150gr 300 BLK showing off some perfect expansion and bullet weight retention.

If you want to push it supersonic, things like Speer Gold Dot are simply amazing for personal defense.


Okay, 300 BLK might not be the best for this. Ammo isn’t crazy expensive (normally) but it isn’t cheap either.

It might have the ballistics of 7.62×39, but it has a price tag more like .308 Win.


Designed to be quiet and come out of a short barrel, 300 BLK really does that role well.

It’s just easy to suppress and fun to do so. It’s quiet, fairly light on the recoil, and still ballistically sound.

Picking a good can is a must, but once you do you’ll have a tool for life.

Danger: Do Not Mix Your 300 BLK & 5.56 NATO

One of the only true negatives I can say about 300 BLK is that due to what I can only call a design oversight, it is possible to chamber 300 BLK in a 5.56 NATO chamber.

That sounds weird, I know. But it turns out that the ogive of 300 BLK is almost perfectly placed to fit against the shoulder of a 5.56 chamber.

223 chamber 300 AAC blackout

Since the bolt face is the same and the magazines are the same, it’s totally possible to accidentally strip a round from a magazine and load a random 300 BLK into a 5.56 AR-15.

The result is bad, very bad. It will literally kaboom your rifle. I’m talking full-on blown in half.

Make sure to keep your ammo and magazines separate. Personally, I never even take 300 BLK with me when I’m shooting 5.56 NATO on the same day.

I also keep separate magazines and range bags, just in case.

Stay frosty and you’ll stay safe.

Best 300 BLK Uppers

Palmetto State Armory

There really isn’t a lot to be said about PSA uppers that we haven’t said before.

You can count on PSA to deliver a quality product for a really good price and that is exactly what they do with their 300 BLK uppers.

From 9″ to 16″, they have a huge range of options waiting for you to choose from.

Their uppers come with a BCG and CH to make them a better deal and easier to get running from day 1.

While PSA isn’t the prettiest or swankiest of uppers, they are highly functional and will get the job done.

Aero Precision M4E1

A step up from PSA in fit and finish, Aero Precision makes an outstanding upper in all of their calibers.

For a good 300 BLK upper at a decent price, Aero Precision is some of the best bang-for-your-buck that you can find.

Using Ballistic Advantage barrels, their in-house Aero handguards, and Aero BCGs — these are simply great uppers that you won’t regret getting.

BCM MK2 Standard

If I needed a 300 BLK upper that I truly had to trust my life to, I wouldn’t feel unsafe at all by picking a BCM.

The quality control that BCM puts its parts through is nothing short of legendary. Lemons and issues are almost unheard of.

Plus their handguard is considered one of the best, their charging handles are awesome, and their BCGs are highly respected.

You can choose from a 9″ model and a 16″ model so either way, you’re covered.

BONUS OFFER: Get your free shooting range targets to print at home!

Get your free targets to print at home!

Subscribe to our newsletter and get gun deals, educational content, hand's on reviews and news on law changes!

Best 300 BLK Complete AR-15s

Q Honey Badger

Get ready to break open some piggy banks for this one, but if you want one of the best 300 BLK firearms ever made — the Honey Badger is it.

From a crazy good, Q-made trigger to the special Q pistol brace to the 7″ barrel, this is one lean and mean little pistol.

At barely over 4 pounds, it really doesn’t get much lighter or handier than the Honey Badger.

Maybe a little overkill for fun at the range or icing hogs with, but overkill is underrated.

Daniel Defense DDM4 PDW

A full $1,000 cheaper than the Honey Badger, this is another pistol that can face the end of the world.

Daniel Defense has a long history of making firearms for special forces both here and internationally and their civilian side firearms are held to the same ultra-high standards.

In fact, DD is one of the very few brands that I would trust my life to right out of the box.

The DDM4 PDW is an AR-15 pistol with a 7″ barrel, weighs 5.7 pounds, and comes with a Maxim Defense CQB Pistol Brace and a linear compensator.

Plus, a small handstop so you keep those digits away from the muzzle.

Aero Precision M4E1

An AR-15 that we’ve recommended a lot, but this time in 300 BLK. Aero Precision is in my mind the best brand offering value to cost right now.

These are solid ARs, well made, accurate, and with exactly the features you need without anything extra to inflate the price.

A big upgrade in durability and reliability over the budget brands, Aero Precision is at the level when you really get a lot for your dollars.

Alternative Firearms In 300 BLK

Howa 1500 Mini Action

It might seem a little odd, but a bolt action 300 BLK is actually pretty cool.

Super ultra-quiet with a suppressor, the Howa 1500 Mini Action is exactly what it sounds like. The legendary 1500 action, but smaller.

What you get is a super lightweight rifle that is able to be almost totally silent but still very deadly.

This ultra-small, ultra-compact, ultra-light rifle is perfect for smaller/younger hunters, woods hunters that want to relax, or anyone that doesn’t want to hike around with an AR on their shoulder.

Sig Sauer MCX

One of the most badass lines of firearms right now, Sig Sauer is knocking it out of the park with the MCX.

You can configure these in any possible way you want with over 500 combinations.

What really sets them apart is the fact that these do not require a buffer tube like we’re so used to with the AR-15.

Instead, these all have folding stocks and can fire while folded. Combine that with their wonderful handguards, triggers, grips, and unbeatable durability — these very well might be the next evolution of combat arms.

Desert Tech MDRx

One of the best bullpup rifles ever made, the MDRx is really making a name for itself.

A huge draw for the MRDx is that it can be converted into a whole host of different calibers.

300 BLK is one of their newest options but you can also pick from 5.56 NATO, .308 Win, and 6.5 Creedmoor all in the same rifle.

If you want small, a bullpup is a way to do it. 

You get all of the benefits of a large magazine and semi-auto fire but in a much smaller package.

With a full-size barrel, you’re also able to make the best out of whatever ammo you have in the rifle.

This one ain’t cheap, but you get a whole lot of guns for your money. Plus, you’re just a conversion kit away from many more calibers.

Ruger Mini-14 Tactical

Simply a cool little rifle, the Mini-14 is effectively what you would have if you took an M14 and downsized it into a much smaller rifle.

Kind of like how the AR-10 became the AR-15, except the Mini-14 came a long long time after the M14 was already replaced in service.

The point is — this is a fun rifle.

And it is much less “scary” than a normal AR-15. So if you’re worried about what the neighbors might think, this is a great way to relax them.

But even though it looks tame, it isn’t.

30 round magazines, 16″ barrels, these rifles are ready to rock.

Best 300 Blackout Ammo

Most of these are available in both subsonic and supersonic options, it just depends on the bullet weight you go for. I’ve listed most of these as the subsonic version since that is really where 300 BLK shines the most

145gr Wolf 

It’s cheap, it’s steel cased, and it always goes bang.

You get what you pay for and this is the plinking grade stuff, at best. I wouldn’t trust it with my life or the life of a game animal, but it’s good for turning money into noise at the range.

208gr Hornady Black

One of my favorite types of 300 BLK, Hornady Black is some high-quality stuff and great for dropping game quickly.

You can get it in both super and subsonic, whatever you like most.

I have always had outstanding precision results with Hornady Black, my Howa 1500 in 300 BLK would shoot about .76 MOA consistently. Awesome.

200gr Sellier & Bellot

More on the plinking side of things, this is a step above Wolf but won’t break the bank. It still isn’t what I would choose for hunting, but I wouldn’t turn it down for defending myself.

Sellier & Bellot are reliable, shoot great, and come in at a decent price.

205gr Sig Sauer

Sig has a number of options in super and subsonic plus they even have all-copper lead-free hunting options for states that require that kind of thing.

I LOVE Sig ammo. It has always done amazing for me and I’ve never been disappointed.

Sig also has been keeping it in stock a lot lately so odds are good that you can actually get some.

210gr Speer Gold Dot

One of the gold standards in defense ammo, the Speer Gold Dot is a monster in any caliber. 300 BLK with its big bullet is a perfect example of how to put down a meat target.

The downside is that it’s not cheap and it can be hard to find even when times are good.

Wrapping Up

This was a ton of information so if you made it this far, great job!

300 BLK is a multitool of a cartridge that can fill a lot of holes and do a lot of jobs.

While it has some limitations in range, as long as you stay within the effective range of about 300 yards — this is a beast of a round!

You might also enjoy

Leave a Reply

Your email address will not be published. Required fields are marked *

Related Posts
Read More

.243 Win vs .270 Win – Cartridge Comparison

In this Article: RecoilBallisticsTrajectoryStopping PowerAccuracyPrice & AvailabilityApplicationsBest Rounds When comparing the .243 vs .270 Winchesters, we are looking at two well-known and popular rounds that overlap in their shooting applications. While there is overlap, there are areas where one cartridge is going to be better suited than the other. I’ll be up front, for this ... Read more
Read More

The Best .22 LR Ammo

Small game fear it, kids love it, and it won’t murder your wallet – the best .22 LR ammo! From your first gunshot as a child to the latest competition caliber you shot last weekend, .22 LR never stops. For most of us, .22 LR was the first cartridge we ever shot. It’s rare that ... Read more

Talk to me

Hi! I'm Mike, one of the oldest writer of Sniper Country! If you have any feedback or question about my articles, please submit it here, it's always appreciated!

[contact-form-7 404 "Not Found"]

Claim your targets for free (worth $99)!

Join 212,000 avid gun enthusiasts and claim your print-at-home shooting drills. Receive exclusive gun deals once a week and all our great reviews right in your inbox.