Born just over a decade ago from a need for a specialized close-combat round for unnamed military special operators, the .300 AAC Blackout has gone on to become one of the most popular chamberings for the AR-15 style platform and with good reason.
However, with over 60 rifle makers today currently producing .300 BLK-chambered firearms, figuring out the best choice takes a little navigating. Rest assured, though, we are here to light the way.
.300 BLK Rifles Comparison
What is the .300 Blackout?
A concept very close to what is today’s .300 Blackout can be found as a footnote in the Individual Multi-Purpose weapon program (IWP).
Well, back in the 1960s, Dale Davis of U.S. Air Force Armament Laboratory began to actively prototype the innovative IMP as an aircrew survival gun for downed pilots.
Eventually chambered in .221 Fireball (5.56x36mm), one of the original concepts for the gun was that it should be chambered for a forward-looking though experimental 7.62x28mm cartridge, using a stubby 81-grain bullet that was still small enough to fit in a standard M16 magazine. In the end, the IMP– later classified as the GUU-4/P by the Air Force– was not adopted and faded into history.
What about Whisper?
While the IMP was a miss, the .221 Fireball (coincidentally the highest velocity pistol cartridge ever loaded by a major ammunition maker – with a SAAMI maximum mean pressure is 52,000 cupw) became a favorite with wildcat cartridge makers, wizened hand loaders who stretch the envelope of what is commercially available.
By the early 1990s, J. D. Jones, the famous gun writer and cartridge designer, had pioneered the use of a specialized cartridge, termed the .300 Whisper, which took a .221 Fireball case and necked it up to take a .30-caliber bullet. The Whisper earned its name due to the fact it was specifically designed to perform well in suppressed platforms.
Using a fat 200-grain bullet, the 7.82x38mm cartridge generated a velocity of just ~1,000 feet per second. This was lower than the speed of sound, which is around 1125 fps, thus eliminating the supersonic “crack” created by the bullet, aiding in better suppressing the round. Smaller bullets, down to 125-grain, moved much faster for those not seeking optimal sound moderation.
The .300 Whisper, however, barely moved the needle with major gun companies in the 1990s, remaining largely in the territory of aftermarket custom barrel and AR upper makers.
The truth was that private “silencer” ownership was extremely rare at the time. It should be noted that in 1993, the ATF only logged 310 Form 1s to produce NFA-registered devices such as suppressors. As such, few manufacturers chambered rifles for .300 Whisper such as the short-lived Loki Fenrir– although Smith & Wesson did produce a short run of M&P-15s chambered for the cartridge.
Other brand-new .30-caliber AR rounds of the era, such as the .30 Remington AR and.30 Gremlin, while not designed for suppressed use, likewise had short lives.
What to Look for in a Quality .300 Blackout Firearm
1. Easy Suppression
Robert Silvers of suppressor maker Advanced Armament Company– a brilliant outfit that yielded some of the most important development in quiet time and eventually spun off the legendary John Hollister who went on to form Sig Sauer’s suppressor division– in a 2012 interview confirmed that AAC’s in-house development of the .300 Blackout began in 2009 as a result of a very specific requirement for an unnamed client that was seeking a .30 caliber AR-style platform that was reliable and suppressor-ready.
At the time, Navy SEALs and Army Delta operators were utilizing the Heckler & Koch MP5-SD, an integrally suppressed 9mm submachine gun, for close-in action at bad-breath distances.
2. More Energy Than a 7.62x39 When Suppressed
Using the 7.62x35mm .300 BLK, a modified AR platform firing it had easily suppressed ammunition that produced more energy than the 7.62x39mm — the same round used by the AK-47 around the world– and remained extremely effective even from very short barrels.
When used with an integrally suppressed barrel, this gun, referred to by Silvers in a DOD paper as the Low-Visibility Carbine or LVC “Honey Badger,” would be “as quiet as an MP5-SD, but with 3x the range” and able to tackle threats out past 100 yards, something no 9mm could ever do.
Further, while the Whisper had never caught on, 2010 was a much different time as ATF records show that 285,087 silencers were in circulation then, a huge increase from past years.
3. AR-Platform Compatibility
With that in mind, ammo maker Hornady brought the .300 BLK to market by 2011 after getting SAAMI certification for the cartridge, something the Whisper never achieved, and gun makers began making ARs to chamber the round, starting with big-name companies such as Sig Sauer.
That year, then-Staff Sgt. Daniel Horner of the US Army’s Marksmanship Unit, using hand-loaded .300 BLK in a custom AR, won the USPSA Multigun National Championships. Today, of course, Horner has won Multigun Nationals 10 times and currently leads Team Sig Sauer.
Meanwhile, there are more than 1.5 million suppressors in circulation, with .300 BLK going a long way to grow that pool.
Why Use the Blackout?
1. Perfect for Pistols
A short, stubby round, the .300 BLK delivers better performance in most loads than the 7.62x39mm at 300 yards. Tests by AAC in 2012 (and keep in mind that ballistics have improved since then) showed that the cartridge could still be effective out to 440 yards– when fired from a barrel as short as 9-inches, making it ideal for use in AR pistols.
This holds true for both suppressed and unsuppressed .300 platforms. Further, while you could step up to an AR-10/SR-25 platform that uses a .308 Winchester round, you gain mass and lose magazine capacity.
2. Uses AR Magazines, Bolt Heads, & Lower Internals
A .300 Blackout-chambered AR-15 still uses the same magazines without a loss of capacity, i.e. a 30-round 5.56 NATO AR mag will still hold 30 rounds of Blackout.
Indeed, it even uses the same bolt head and lower receiver internals as the 5.56.
In short, for military and law-enforcement applications, a .300 Blackout-chambered M4 makes an ideal sub-gun replacement, delivering a cartridge many times more effective than a 9mm pistol caliber MP5. For home defense, the same thing can be said in a .300-chambered AR replacing pistol caliber carbines.
For hunters, the round makes for an ideal lightweight, close range, deer and wild hog gun, great for use in areas of heavy brush.
3. Huge Array of Bullet Weights
Described by some as “the .30-30 for an AR-15” the .300 BLK is actually much more than that as it allows everything from heavy subsonic bullets, such as Hornady’s 190-grain Sub-X TAP– a round recently chosen for CQB use by an undisclosed “specialized unit” inside the Department of Defense, doubling down on the original concept– to more spicy supersonic loads with smaller bullets in the 100-grain range.
As about the largest a .223 Remington will allow in an AR is a 77-grain bullet, the bigger pill of the Blackout delivers.
4. Just Swap the Upper
Further, since the .300 works in a regular AR mag, most standard AR-15s can quickly utilize the round after nothing more than a swap of the upper receiver.
The Best .300 Blackout Pistols & Rifles Reviewed
1. Top Choice: Palmetto State Armory
Few brands deliver the value of Palmetto State when it comes to the AR platform, and their 16″ .300BLK rifle is no exception.
Their PA-15 Rifle in .300BLK pairs a 16″ chrome-moly steel barrel with an ideal 1:8 twist, M4 barrel extension for reliable feeds, and a pistol-length gas system. That shorter gas system pairs well with a suppressor, which the .300BLK runs flawlessly and makes an ideal hunting or suppressed home defense rifle,
In addition, the PA-15 runs a PSA 13.5″ lightweight M-Lok free-float handguard, low-profile gas block, and A2 flash hider for that classic look.
2. Barrett Firearms
When you say, “Barrett,” most people think of their long-range .50-caliber BMG rifles, but the Tennessee-based company also cranks out a variety of popular AR platforms, with their high-quality direct-impingement REC7 DI models being front and center.
Besides standard 5.56 NATO variants, Barret also markets the rifle in 6.8 SPC and .300 BLK format with options for either 16- or 18-inch barrels and ALG triggers.
3. Bravo Company
Wisconsin-based Bravo Company has grown to become a household name in the AR game and their CQB series guns are crowd-pleasers with consumers seeking a 300 BLK rifle around the $1K-ish price tag that delivers above its weight class.
The company offers the mid-range CQB KMR-A and MCR carbine varieties, differing in the style of their handguards and gas systems. Easy on the back, each comes in at just 6-pounds.
4. Daniel Defense
Daniel Defense is an old hat when it comes to providing high-speed platforms to high-speed customers, such as their MK18s to the U.S. Navy SEALs.
True to form, DD has off and on produced examples of their ISR, or Integrally Suppressed Rifle, for consumers. Chambered in .300 BLK, it uses a 9-inch S2W profile barrel with a permanently attached integral suppressor to make it 16.1-inches long, keeping the tax stamps down to just the one.
With subsonic loads, it is almost Hollywood quiet, right off the shelf.
5. Diamondback Firearms
Florida-based Diamondback is a budget AR maker that doesn’t disappoint and has been in the .300 Blackout game since 2014 with their DB15 series rifles.
Best yet, other than Magpul hardware and mags, they produce just about everything in-house with excellent quality control, which is an outstanding deal when you consider you can usually get into one of these for about $800.
6. FN Firearms
A good portion of the M16s and M4s delivered to the U.S. Army in the past 30 years have rolled out of FN’s factories, making them a serious expert on the subject.
Not to let their fans out of uniform down, the company’s FN-15 Tactical is offered in .300 BLK complete with the same combat trigger, cold-hammer-forged chrome-lined barrel, snappy trigger pull and rail system as on their military schedule rifles. Hard to beat.
7. LWRC Firearms
Fitted with a 16.1-inch spiral fluted barrel, Monoforge one-piece upper, and fully ambi lower, LWRC’s direct-impingement IC-DI platform comes not only in your standard vanilla 5.56 NATO but also in the super-duper rocky road that is .300 BLK.
Once you pick up one of these, have your billfold closed because you will not want to put it back down unless it is in your gun safe.
8. Noveske Firearms
Grants Pass, Oregon is home to the legend that is Noveske Rifleworks and their 6-pound Light Recce .300 BLK build includes a Magpul CTR stock, and ALG ACT trigger, iron backup sights in a world where plastic is the norm, and a 16-inch cold-hammer forged barrel.
It is meant for hard and prolonged use, having double aluminum heat shields on the handguard, Type III hard-coat anodizing, and extended feed ramps.
9. Primary Weapons Systems
Idaho’s Primary Weapon Systems may not be a name you hear when shopping big box sporting goods stores of local gun shops, but those who know PWS love their work.
The company’s MK116 long-stroke piston action rifles are available in at least four different mods chambered in .300 BLK with options to include KeyMod or Magpul M-LOK handguards, Bravo Company PNT or Zev SSR triggers, and forged or lightweight uppers.
- ATF, Firearms Commerce in the United States, 2011, Pg 22
- FAS.org, Multipurpose Individual Munition (MPIM)
- ChuckHawks, .221 Remington Fireball
- SAAMI, Commercial Centerfire Pistol Pressure and Velocity Performance Standards
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