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Ultimate .300 Blackout Barrel Guide

Michael Crites

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Selecting the perfect barrel chambered in .300 AAC Blackout can be a little tricky as one has to take into account everything from materials and contour to twist rates and lengths, but I take it step-by-step and light the way to keep you on path to your ideal new barrel.

In This Article:

.300 BLK Barrel Comparison

Below is my list of the best .300 BLK AR barrels for 2021. I list the best choices in terms of value, performance, design, and cost.

Click on the name to head to the product page, read reviews and check prices or skip ahead to the list of barrels.

10 Best .300 BLK Pistol/SBR barrels

1. Ballistic Advantage 8.3" .300 BLK Barrel

A great maker of shorty .300 barrels that all clock in at under $200 smackers, Ballistic Advantage makes 6, 8, 8.3, 9, 10, and 10.5-inch 300 Blackout barrels with the company’s Modern series being more of a budget line while their Hanson models are a tad better.

With that, I love their 8.3 Hanson profile barrel as it is 416SS in construction and uses nickel boron-coated M4 feed ramp extensions. What is a Hanson? BA’s in-house Hanson profile barrels feature a shoulder-less design, symmetrically limiting barrel “whip” and allowing the barrel to quickly return to its home position.

As described by the company, it “provides a lightweight feel without lightweight limitations.”

2. Anderson 10" .300 Blackout Pistol Barrel

Oft derided as the “Poverty Pony” when it comes to black rifle components, Anderson is making some decent stuff these days despite the haters. As a bonus, they are priced right as well, with a lot of their .300 Blackout barrels hitting the $100~ mark, which is great for those looking for a budget build.

When it comes to pistol/SBR length barrels, Anderson makes a 1:7 twist 7.5-inch with a Government contour as well as a 1:8 twist 10-inch. Both are 4150 with a Nitride finish and support a standard and adjustable gas block.

3. Bear Creek 7.5" .300 Blackout AR-15 Barrel

Bear Creek Arsenal makes over a dozen different .300 Blackout barrels in both pistol/SBR and carbine length. While they make some wallet-friendly 4150 models, they also do great work in 416R stainless. 

With that, I like their 1:8 twist 7.5-inch stainless barrel which is backed by a lifetime warranty and supports both a standard and low profile gas block. Of note, they recommend PPU Rifle Line 125-grain for use with this one.

4. Daniel Defense 10.3" 300BLK AR Pistol Barrel

Georgia-based Daniel Defense is to ARs what Jeep was to utility vehicles. Besides their all-up rifles, DD also makes their fine 4150 cold-hammer-forged barrels available to consumers to “roll their own” so to speak. 

When it comes to .300 Blackout pistols, Daniel has a great chrome-lined 10.3-inch model with a 1:8 twist and heavy Mil-spec heavy phosphate coating that is hard to beat. Weight is a handy 20-ounces.

5. Diamondback .300 AAC Blackout Pistol-Length Barrel

Florida’s Diamondback doesn’t get the love that black rifle players like FN or Wilson Combat does, or the attention from the aggressive peasantry that Anderson and PSA enjoys, but for people looking for an affordable option for good quality barrels, DB should be on the radar. 

They make a sweet low price 10-incher 300 Blackout with a heavy profile that deserves a look, not only because it is made of 4150 steel with button-rifled 6-groove rifling and M4 feed ramps, but because it runs under a hundo.

6. Faxon Match Series 9" Gunner 300 BLK Barrel

If Daniel Defense is the Jeep of AR barrels, then Faxon Firearms is surely the Cadillac. They carry nearly a dozen .300 Blackout pipes in their catalog off and on, loaded with pistol/SBR barrels in the 7.5, 9, and 10.5-inch range. 

The gold standard of these is their Match series 9-inch Gunner model. Constructed of 416R stainless and black nitrided against wear, it has precision 5R rifling. 

The “Gunner” refers to Faxon’s in-house hybrid profile– a blend of Gov’t and Pencil– that is billed as bringing the balance of the barrel back towards the shooter’s body, limiting fatigue, and allowing for shooting, training, or hunting all day long. Weight is just under a pound.

7. KAK 300 BLK 6.25-inch "Baby Blond" AR Barrel

KAK Industry is well known among fans of the .300 Blackout for their barrels as they make a broad range of offerings including “Value Line” specimens with Melonite finishes that run about $100 complemented by more bespoke “Blonde Line” models. 

Speaking to the latter, they also make some of the shortest .300s available including 4.75- and 6.25-inchers for those looking to get really abbreviated. 

KAK’s 6.25 Baby Blonde, built from a 416SS Green Mountain barrel blank, has 5R rifling with a 1:7 twist, M4 feed ramps, and a matte blasted very distinctive grey finish. Despite its dwarf size, using a standard weight buffer, pistol gas tube, and gas block, it can run supersonic loads both suppressed and unsuppressed as well as fat subsonics with a can attached.

8. Noveske Lo-Pro Gas Block 300 AAC Blackout Barrel

Oregon-based Noveske only makes black rifles and black rifle components and their .300 Blackout barrel systems cater almost exclusively to the very short. 

Their Lo-Pro Gas Block Barrel is available in 7.94, 10.5, and 12.5-inch models with a 1:7 twist. Noveske also makes a lightweight contour barrel in 10.5, optimized to run very heavy 208-220 grain ammo.

9. ODIN .300 Blackout 10.5" Pistol Barrel

Idaho-based ODIN Works is one of those word-of-mouth kinds of operations that stays that way because people don’t want to ruin a good thing by giving it too much publicity. 

The company’s superb .300 Blackout barrels include 8- and 10.5-inch models. Featuring hand-lapped rifling and 416R construction with a medium profile, these barrels shoot as good as they look.0.5-inch models. Featuring hand-lapped rifling and 416R construction with a medium profile, these barrels shoot as good as they look.

10. PSA AR-15 10.5" .300 AAC Blackout Pistol Barrel

South Carolina’s Palmetto State Armory, off and on, makes a whole line of .300 Blackout pistol barrels, offering 7.5, 8, 8.5, and 10.5-inch models at a decent price with nitrided or manganese phosphate finishes. 

Our favorite of their line when it comes to balancing performance and cost is their 10.5 1:8 twist phosphate barrel. Shipping standard with an M4 feed ramp extension, it offers 4150 steel construction and typically runs just over $100.

10 Best .300 BLK Carbine Barrels

1. Ballistic Advantage 16" .300 Blackout Barrel

About the only offering that BA has for rifle-length .300 Blackout barrels is a 16-inch Modern-series offering. However, it’s a good one, being a 1:7 twist 4150 chrome moly with a QPQ corrosion resistant finish and QPQ coated M4 feed ramp extension for under $200.

Weight is a fairly stout 28.9 ounces due to its DRP profile, which is BA’s in-house hybrid heavy contour that is “designed with a little more wall so that heat is more easily dissipated, and barrel whip is kept to a minimum.”

2. Anderson 16" .300 Blackout Barrel

One of the biggest fish in the budget black rifle builder marker pond, Anderson makes some decent barrels for .300 Blackout carbines at a great price.

A good one that hits all the marks for an entry-level barrel is Anderson’s 16-inch 1:8 twist Government profile barrel, which can typically be had for $150 or less.

3. Bear Creek 16" .300 Blackout Barrel

Bear Creek Arsenal’s Bear Claw may sound like a pastry but make no mistake, it is actually their line of fluted rifle barrels made from 416R stainless with a black nitride finish. They both look great and are precisely rifled for high accuracy. Their Bear Claw .300 Blackout carbine model runs 16-inches and carries a 1:8 twist rate.

4. Daniel Defense 16" .300 Blackout Carbine Barrel

Georgia’s Daniel Defense, always a big player in everything AR, makes an excellent 16-inch .300 Blackout barrel that they sell to the public.

With an S2W profile– Daniel’s Heavy contour– it is constructed of cold hammer-forged from 4150 with a Mil-spec heavy phosphate coating and a chrome-lined 1:8 twist on a carbine length gas system & adjustable gas block. Pushing 37 ounces, it is also kinda expensive, usually running just over $300, but hey, chrome-lined usually don’t come cheap.

5. Diamondback 16" .300 AAC Blackout Heavy Barrel

As a great alternative to budget lines such as Anderson and PSA, Diamondback offers a 16-inch 1:8 twist .300 Blackout barrel that usually can be found for sub-$100.

A heavy profile 4150 steel barrel with a black nitride finish, it has a button-rifled 6-groove bore, is 11-degree target crowned, and comes complete with M4 feed ramps, all things that make it tough to beat for the price.

6. Faxon Match Series 16" Flame Fluted 300 BLK Barrel

One of the best .300 Blackout carbine barrels ever made for the consumer market is Faxon’s 16-inch flame-fluted Match series barrel. With a 1:8 twist and 5R button rifling, this 416R steel barrel only weighs 26-ounces.

Nitrided inside and out, the variable-depth fluting also gives the barrel an unmistakable look that screams for a handguard with lots of slots to show it off properly. Who says you cannot look good while ringing the “x”?

7. KAK 16" .300 BLK Carbine Melonite Barrel

KAK Industry has long answered the call to supply .300 Blackout barrels to enthusiasts of all sorts. When it comes to carbine-length Blackout models, they make a no-frills Melonite finished 16-inch model with a 1:8 twist and a medium-light contour.

Weight is 27.5-ounces, and the barrel includes M4 feed ramp extensions.

7. Noveske

Noveske is the Ferrari of .300 Blackout barrel makers and they only currently make a single carbine-length 16-inch model, their Lo-Pro Gas Block Barrel.

The barrel is tuned to lock back on the last round using subsonic 220 and 208-grain ammunition with a sound suppressor with symmetrical baffle stacked cans such as the AAC Cyclone K, 762-SDN6, and Surefire 762K. The bragging rights for this beauty will set you back $500– if you are lucky enough to find one in stock.

8. ODIN Works .300 Blackout 16.1" Carbine Barrel

Specializing in pistol/SBR-length barrels (who doesn’t when it comes to .300 Blackout ?!) ODIN Works does offer a single excellent carbine-length model, a 16-inch 416SS model that comes with button-rifled 1:8 twist rifling. This medium-profile barrel includes M4 feed ramps and a gas port that supports both a standard and adjustable gas block.

10. PSA 16" AR-15 .300AAC Blackout Barrel

Palmetto State Armory’s best contender when it comes to 16-inch .300 BLK barrels is probably their PSA-branded 4150 steel nitrided barrel, which runs an industry-standard 1:8 twist and carries an M4 feed ramp extension with support for both a standard and adjustable gas block.

Essential .300 Blackout Barrel Features

The .300BLK gives you the girth of the .308 -- with half the powder load.

Pistol or Carbine Length?

First off, as the hallmark of the .300 BLK is its ability to operate successfully in the short space – allowing it to be optimized for use in AR platform barrels down to 7.5-inches in length — it is important to decide on whether to go pistol or rifle with your build. Due to National Firearms Act (aka “Class III”) regulations as interpreted and enforced by the ATF, the minimum barrel length for a rifle is 16-inches and at least 26 inches in overall length. Anything shorter, by definition, is a pistol so long as it doesn’t have a stock, or a short-barreled rifle if it does.

 As typical ballistics envelopes on the .300 BLK– as it fires roughly the same sized bullet as a .308 Winchester but with half the powder– have the round performing best at ranges from the muzzle to about 200 yards, and shining at 100 or less, even with a very short barrel length running subsonic loads or supersonic ammunition, it is truly up to the user to pick whether they want to run a pistol/Short Barreled Rifle (SBR) or a carbine AR platform. 

Smaller guns are great for use with 300 Blackout barrels in heavy brush, such as when hunting feral hogs in dense vegetation, or in self-defense engagements in built-up/urban areas such as in-home protection using suppressed fire. 

Meanwhile, rifles with longer 300 Blackout barrels will have better accuracy potential, especially at range, due to an extended sight radius, offer more handguard space for accessories, and add more velocity to bullets fired through its muzzle, translating to more energy, effective range, and a better power curve — even when running subsonic loads.

 Further, remember that the .300 BLK was created specifically for use in short barrels with heavy bullet loads, and once you start stretching out to carbine length (i.e., 16-inches plus) you may have teething problems cycling heavy subsonic loads. 

So, if you are looking for a dependable suppressor host, you may want to stick with something short.

 Just go into it with your eyes open as to what you are looking for before you choose short or long barrels, as each has its plusses and minuses.

Materials

The four most common steels used for .300 BLK barrels are 4140/4150 steel or 416SS/416R steel. All “41xx” steels are chromium-molybdenum alloy (seen as or “chrome-moly” or “CrMo” in ad copy, sometimes with Vanadium mentioned as “CrMoV”), and have excellent strength for the weight, hence their use in barrel making.

The difference between 4140 and 4150 is that the latter has slightly more carbon in the alloy (that’s what the “50” means over the “40”), thus making it just a bit harder. Most military AR 15 M4 type barrels are 4150, for reference.

When it comes to 416, this is one of the first free-machining stainless steels– although they can still rust and corrode as they are not “true” stainless steels– but they do have excellent corrosion and oxidation resistance while still being extremely hard, harder than 4140/4150 steels.

Between the assorted types of 416, 416R has better resistance to extreme freezing weather while both can accept long-wearing precision rifling.

In a nutshell, 4140 is going to be the least expensive or “budget” barrel, while 4150 and 416 steels are better and best.

Contour

Barrel contour and profile have a lot to do with both performance and overall weight. Heavy contour barrels are more stable which leads to better accuracy and less “whipsawing,” while the extra “meat” allows for faster heat distribution and dissipation which is good for high rates of fire.

Thinner, pencil barrels can still perform, especially in slow fire, while saving ounces (not to mention cost) in an AR15 build when it comes to weight. A SOCOM contour barrel has a medium contour that better handles longer strings of fire than skinny pencil barrels without having the weight of a heavy profile barrel. “Government” profile barrels have more beef but have largely been replaced in popularity by SOCOMs, for good reasons.

Going past this, several AR 15 barrel makers have their own internal SOCOM-like profiles, developed from experience and feedback with the design. Good examples of this are Faxon’s Gunner profile and Ballistic Advantage’s Hanson profile.

Twist

The “twist” of a rifle barrel refers to the rifling in terms of how many inches it takes for the bullet to make a full rotation down the barrel. For instance, a 1:10 twist means that it takes 10-inches for a bullet to rotate fully at that rate. The tighter the twist, in other words, is shown by a smaller number, while a looser or longer twist is shown by a higher number. Almost all common .300 BLK AR 15 barrels carry either a 1:7 or 1:8 twist with 1:10 and 1:12 also being less frequently available.

For routine use with most heavyweight bullets (to 180-230 grains) 1:8 is preferred while 1:7 is better to help stabilize heavier/longer bullets.

The looser twists of the 1:10 and 1:12 rates are best for lightweight bullets (80 to 130 grains) with all rated as being equally mediocre when it comes to wringing performance with mid-weight bullets that fall between those two bookends.

Rifling

Rifling types seen in .300 BLK barrels are typically cut rifling, button rifling, and 5R. While I can wax on about the history, attributes, and pitfalls behind each, the abbreviated version is that button rifling is about the most commonly encountered when it comes to .300 BLK as it is easy to do– making it an inexpensive and short process for manufacturers– thus resulting in a more affordable AR 15 barrel that is still acceptably accurate due to its consistent bore and groove dimensions.

Cut rifling and 5R are more time-consuming– which translate to more expense and often much heavier barrels– but can produce more accurate barrels.

Considerations

The circa 2011 Advanced Armament Company's .300 Blackout AR-15 platform
The minute the .300BLK was introduced, it didn't take a rocket scientist to figure out that it had solid prospects for the savvy consumer looking for a great mid-range carbine or AR-style pistol that far outclassed a 5.56 while working in a more accurate platform than a Kalashnikov. 

Purpose

The .300 BLK excels at what it was designed for: being a comparably fat .30-caliber round that could beat the 5.56 NATO/.223 Rem in performance at everything under 200 yards while offering a subsonic velocity profile that allowed for effective use with suppressors on the AR platform.

Since its introduction, supersonic rounds have hit the market to expand this narrow envelope to offer more choices to consumers, giving Blackout fans who were fine with going supersonic a lot more range with lighter bullets.

With that, it is important to figure out what kind of .300 BLK build you are going for and shape your barrel (and bolt and other component) choices around that. Want a knock-around gun for hunting in the heavy brush? Purchase a lighter profile to save weight paired with a muzzle brake and figure out your twist rate from what grain bullets you intend to use.

Don’t be afraid to go quiet, as it is an option in something like 40 states to harvest game with a suppressed firearm making a 300 Blackout barrel and suppressor an excellent choice.

Want something for home defense? In that case, you may want to go with more of a heavy or SOCOM profile barrel– after all, you aren’t likely to carry the rifle a long way, so a couple of extra ounces aren’t a dealbreaker — with a corresponding twist rate for the intended load.

Remember, start with your purpose in mind and work from there rather than picking a barrel and working backward to justify it.

Life cycle, or "How long will a 300 BLK barrel last?"

The first time you fire a round through a barrel, it starts to erode and will continue to do so until the barrel is “wrung out,” and fails to adequately stabilize bullets anymore, translating to “keyholing” on target and abysmal accuracy/performance. How long does this take to occur? Well, that depends.

The basic rule of thumb for high-velocity centerfire rifle barrels with a light contour/profile is a lifespan of 2,000 to 5,000 rounds of hard use. Naturally, heavier barrels tend to allow for higher round counts due to their ability to dissipate heat faster and better maintain harmonics. Gratefully, an easy fix to help extend the lifespan is simply cleaning out the brass, lead spall, and corrosive fouling between range trips rather than letting it build up and possibly pit the barrel. Products like a good bore paste can help condition a barrel after cleaning. Likewise, higher quality barrels such as hard/high-speed stainless steel (e.g., 416) and the like will have a longer barrel life.

Further, nitriding can help withstand barrel erosion, allowing a 10,000-round lifespan. Chrome lining, common in military applications, can greatly extend barrel life, pushing into the 20,000 round range if properly maintained.

In short, if you plan to run a barrel a long time, look for those that are stainless, nitrided, and or chrome-lined. If opting for more budget barrels, plan to get another once you start pushing past 5K rounds if you want to maintain accuracy. Either way, keep your barrel clean and protected to ensure you get what you paid for.

History of the .300 BLK

If you remember anything at all about the development of the .300 Blackout cartridge by AAC circa around 2009, you will recall that the round sprang from an extremely specific requirement for an unnamed client that was seeking a .30 caliber cartridge that was AR-platform friendly, dependable, suppressor-ready, could run muzzle devices as well as sub and supersonic ammunition, and above all was suited for close-quarters combat.

Ideally, the gun would be the size of a Heckler & Koch MP5, the gold standard for compact and dependable submachine guns running subsonic ammunition for the past half-decade. 

The resulting “Low Visibility Carbine” proposal, dubbed the Honey Badger, delivered a stumpy M4 carbine– optimized for 9-inch barrels and able to go shorter if needed– that delivered a ballistic performance like an AK47 at ranges out to 200 yards and could do so quietly when suppressed and coupled with rounds using heavy bullets that generated subsonic speeds for less on the recoil front.

It could also run supersonic ammo in the weapon when the situation called for it, but operators will need hearing protection for those range days.

However, almost the very minute the round was introduced, it didn’t take a rocket scientist to figure out that it had solid prospects for the savvy consumer looking for a great mid-range carbine or AR-style pistol that far outclassed a 5.56 while working in a more accurate platform than a Kalashnikov. 

From there, the versatile cartridge has gone on in the past decade to become wildly popular for users who choose to hunt medium game (think deer and wild hog), compete in 3-gun matches (SSG Daniel Horner of the USAMU used a 300 race gun to win his 4th USPSA Multi-Gun National Championship), or in-home defense– all hold true today.

Shortcomings

Be extremely careful buying pistol-length (under 16-inch) .300 BLK barrels as simple possession of such a short barrel along with a non-NFA AR-15 lower receiver is prohibited via the concept of “constructive possession” of NFA firearms. It is always a good idea to have your “pistol” marked or “other” receiver on hand before you buy your AR pistol barrel or your Form 1 for making a legal SBR. Your doggo will thank you later.

Another thing to be careful of, when running a suppressor on a very short .300 BLK barrels using heavy subsonic loads, can be issues with off-axis turbulence causing baffle strikes at subsonic velocities on cans that use K type baffles or similar. Check with your suppressor maker beforehand for compatibility to avoid an aggravating suppressor rebuild or potentially uncomfortable lower velocity spontaneous disassembly. Chicks hate that kind of thing.

It’s also decidedly easy to chamber the wrong caliber when running a 5.56 and 300 Blackout barrel, so marking your AR build’s mags and gun parts to prevent unintended consequences is always a good idea.

Closing

Among the crowded field of .300 BLK barrels, it is easy to get lost in the weeds of trying to find “perfect” when, truth be told, there are usually clear-cut reasons to go with one barrel over the next for an AR build.

Just evaluate your needs, balance them against what is out there, and take the plunge into your next favorite AR rig.

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One of the biggest fish in the budget black rifle builder marker pond, Anderson makes some decent barrels for .300 Blackout carbines at a great price. A good one that hits all the marks for an entry-level barrel is Anderson’s 16-inch 1:8 twist Government profile barrel, which can typically be had for $150 or less.

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