300 AAC Blackout 7.62×35 – Rifle Caliber Trends

By John Farnam

300 aac blackout vs 223
300 aac blackout vs 223

Ft Collins, CO –-(Ammoland.com)- I talked today with a friend who works in nuclear security at a major installation.

He is proposing to his superiors converting all existing ARs, currently chambered in 5.56×45 (223), to 7.62×35 (300 Blk) caliber.

It will involve swapping barrels only. Existing magazines will all work, as will existing bolts and bolt-carriers. The entire project can be accomplished quickly, and at modest cost, when compared with buying new rifles.

Selling points are significantly increased range and penetration. They’ll be using a new, 112gr copper/tungsten bullet, designed to easily penetrate car doors, car glass, cinder block, and most body armor, even that which is currently “rifle-rated!”

Penetration is efficacious, out to 300m!

Naturally, there is some institutional push-back from those up the food-chain who need additional convincing, but advantages over conventional 223 ammunition are so significant that I predict this “trend” (if that is the right word) will prove unstoppable!

This is all what the 6.8mmSPC was supposed to do, and probably would have! But, for whatever reasons, the 6.8mm never gained traction. The 6.8 currently has a small following in the civilian shooting community, but major institutional buyers, like the Pentagon and other big, federal consumers, never displayed much more than casual interest.

And, the 7.62×51 (308) still has a substantial following within the active services, and many secretly long for the return of the M14 in general-issue. However, that is not in the cards! The 308 will not make a major ” comeback,” absent an epochal philosophical shift at the highest levels. Right now, that is extremely unlikely!

By contrast, the 7.62×35 is rapidly “catching-on!

Currently, I don’t have a rifle chambered for it, but I will soon!


About John Farnam & Defense Training International, Inc

As a defensive weapons and tactics instructor John Farnam will urge you, based on your own beliefs, to make up your mind in advance as to what you would do when faced with an imminent and unlawful lethal threat. You should, of course, also decide what preparations you should make in advance, if any. Defense Training International wants to make sure that their students fully understand the physical, legal, psychological, and societal consequences of their actions or inactions.

It is our duty to make you aware of certain unpleasant physical realities intrinsic to the Planet Earth. Mr Farnam is happy to be your counselor and advisor. Visit: www.defense-training.com

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Just my “2 cents”, 300 BLK is superior out of short barrel platforms, (performs best in 9″-10 1/2″ barrels, sub-sonic or super-sonic), to the 5.56… It is technically a .308, in a small cartridge; available in much larger grain projectiles than the 5.56. It provides substantially more energy transfer, (= stopping/knock down power), than the 5.56. Both rounds have their particular place. But for shots made 300 yards and inside, home defense, small game, etc, I’ll take my Sig PM400 Scorpion w/9″ barrel, in 300 BLK, over my Colt M4 in 5.56… Heres proof… Round Weight Barrel length Muzzle velocity… Read more »

Sport Shooter

I’m a ar15 Builder/Enthusiast and own a 7″ pistol and 16″ carbine chambered in 300 Blackout and put several thousand rounds through them! There powerful, accurate, dependable, fun to shoot, and the most versatile platform in the ar15 lineup! As far as filling the most roles (sport, self defense, hunting, military, law enforcement) it is my opinion that this is the best the ar15 has to offer at the moment. Currently newly manufactured rounds can be found for 46 cents each and hand loads for about 27 cents in a overwhelming offering of styles and configurations! The 300 Blackout is… Read more »


I have a 300 blackout in pistol form, I went with it because of the cartridges performance from ahort barrels and the interchangeable parts with 223/5.56 mags,bcg. I do think the 6.8 is probably the best of both worlds. I have read 80% of a 308, it may be on my list soon! Economics were my main reason for 300bo.

ed sparks

I have hunted for over thirty years with single shots. I also have been raised around the bench rest tables. I learned to and have shot for fun, hunting and self defense. When it was still legal in Montana to shoot all game animals with a 22 caliber, I used a .223. I chose it for the same reason i chose the single shots, sport and the challenge….hit or miss. Then i designed a predator decoy and my world changed to need more than one bullet, so i bought an AR Remington r-15 when first out. Changed the trigger and… Read more »


Kneauxla, I’m not going to say 40+, but my Ranch rifle has accounted for more than 10 blacktails in the neighborhood of 150-200 pounds. Not one of them went anywhere but down. Every shot was in the heart so bullet placement has a lot to do with that, but if you can’t hit what you’re aiming at, maybe you should pass and wait for a better shot. I have a .300 Win Mag for larger game, like elk, but again, it comes down to putting the bullet where it does the most good, or you’ll be tracking it too. More… Read more »


Tom, the only thing that you said that was right was shot placement. I have hit deer through the heart and blew up the heart and had a much larger exit wound than any 5.56 with a 270 win only to see it go 25′ before dropping, so I know you are full of shit. The only way I know to drop a deer dead right there is to neck shoot him and break his neck. The 5.56mm does not have the energy required to break a deers neck. However, I use my 300 blackout to kill hogs cleanly with… Read more »

Good Ol Dave

I am a big fan of the 5.56. The cartridge has been adopted by armies all over the world for reasons that have nothing to do with “keeping up with the Jones”. Problem is, the cartridge was originally designed for full length rifles; being shot out of carbine length rifles, the bullet exits before the powder is completely burned so the bullet is not travelling in the extra high velocity it needs to fragment and tumble in the way it was meant to. It’s still at a high velocity but it’s pretty much going to just drill a hole right… Read more »


If I’m not mistaken the 300 AAC BLK and the 300 Whisper are one in the same. I don’t know how the 300 BLK compares to the 6.8 SPC but I do know from what I have read (reliable sources) that both the 6.8 and 300 shoot flatter and have more knockdown power at greater ranges than the 5.56 which isn’t saying much. I have a friend that swears by the Remington AR he shoots in the .30 caliber Remington load. It only stands to reason as you’re likely comparing sub 60 grain bullets to 100 grain plus bullets even… Read more »


shot placement you can drop a deer with a 22 long rifle sweet spot high in shoulders


“CPT of the Militia” Ha, man, you are literally off the mark on everything you just said. The only things you got right was that tax stamps cost $200 and that ammo is hard to come by. The facts are that when building a 300BLK AR, you only need to change the barrel, which isn’t out of reach of anybody. The 300 AAC BLK is a reloader’s dream. Anyone else need not apply, stick to your .223 Rem. The rounds are assembled from non-exotic components, and that’s a major advantage. 30 caliber is the most versatile stuff out there for… Read more »

CPT of the Militia

Sorry to say, the market forces are against you. Ammo is both way too expensive and hard to come by; plus buying the hardware ( either complete rifle or barrel, handguard, gastube, sights) is out of reach for many civvie shooters, and what with fed/local budgets on the shrink; so too, big budget PD/ Sheriff or multi million dollar army purchases ( SF went to 6.8 then stalled)… so it’s not going to happen except at the sharpshooter/ collector/ hand loader levels… which is where 6.8 finished up at. Add to this mix shooter confusion on just what pieces do… Read more »


what is this crap sould have looked at porno


I love the .223 cartridge! I’m not a big fan of the .300 BLK, but again I don’t know to much about it. This article has opened my eyes on some of the advantages it has, but I’m not sure it’s the advantages I need. I would like to see something like the .243 in an AR type rifle. It’s an excellent round and very flat shooting. I’m not sure about the .243 round fitting the AR magazines, because I don’t know the measurements. If they could fit in the AR mags, I would try to buy one today. Right… Read more »

Lee Spinner

Remington makes its R-25 in both 308 and 243. The rifle is based on the AR-10, a slightly larger, and stronger, AR.
I have one in 308 and the 243 is just a necked down 308. It’s a great rifle.


“The Blackout is a ho-hum alternative to the 5.56. It has more frontal area, and therefore more presumed stopping power, but it offers less muzzle energy than the 5.56.” Um, no. 300 BLK has as much energy from a 16 inch barrel as 5.56mm does from a 24 inch barrel. “Those who claim superior accuracy should explain why Savage, for quite some time, has refused to manufacture a .300 AAC, claiming they couldn’t get sufficient accuracy out of it.” Savage is the company who made my 10FP rifle that I had to re-thread because the bore had way too much… Read more »


I’m not claiming the 300 Blackout is the greatest thing since sliced bread, but let’s be honest: it does offer advantages over 5.56x45mm. The statement that it offers less muzzle energy than 5.56x45mm is just plain wrong; from equal barrel lengths, comparing 110gr TAC-TX to 5.56x45mm 62gr M855 Ball (the standard military round), 300 BLK offers about 6% more muzzle energy, about 37% more muzzle momentum. Earth-shattering advantage? No. But an advantage in energy and momentum. And there are two other advantages: proportionally much less energy loss from a short barrel, and very effective subsonic loads (up to 240gr bullet).… Read more »


Depends on the definition of “accuracy”, doesn’t it? I bought a S&W upper to “play with”, not expecting too much. I changed my mind very quickly. Given the current shortage of components I’ve had to “make due” with what I could find. Granted, I’ve handloaded for almost 40 years but the 300 AAC was the easiest round I’ve ever worked with to find “a good load”. My definition was “cycle the action” and less than 1 MOA. With only a few exceptions, all sonic loads meet that standard. Sub-sonic, without a “can”, are a different matter and I suspect that… Read more »


The Blackout is a ho-hum alternative to the 5.56. It has more frontal area, and therefore more presumed stopping power, but it offers less muzzle energy than the 5.56. In almost all areas (energy, trajectory, accuracy) it suffers in comparison to the 5.56. In fact, it has considerably less power than the 7.62×39. Just arm yourselves with AK-47s! Those who claim superior accuracy should explain why Savage, for quite some time, has refused to manufacture a .300 AAC, claiming they couldn’t get sufficient accuracy out of it. In all, I agree with the commenter who says it’s like the 6.8… Read more »


I have taken 2 whitetails with the 300 BLK, each at 200 yds broadside shots. One was taken with Barnes 110 gr TAC bullets, the other with 130 gr. barnes loaded in Remington Hog Hammers. Each time the bullet passed through and each deer recovered less than 100 yds from where shot. The 300BLK is no giant killer, but a whitetail is no giant.


The blackout is a great subsonic round, but in full power it is just as mediocre as 7.62×39. The 5.56 is waaay more effective at one shot instant kills with 55gr on deer than the ho-hum ak round will ever be. Far more accurate too. I have killed conservitively 40 some deer with. 223/5.56 over the years and all have gone down on the spot. No running to punmp meat with adrenilan, just instant kills.
Love my blackout/ whisper for subsonic shots with 220gr. tho!


I shoot an AR 7.62×39. I can have inexpensive fun at the range at .22 cents a round and I can harvest deer with soft points at .30 cents a round.
That’s my reason for not having built a 300AAC upper.


Bullshit. this crap is still not better than the 7.62×51 or the 7.62×39. its just another hip “Ar15 trend”, just like the 6.8 was.


I converted to it over a year ago. I handload it and have a SBR chambered in it.


I’ve shot .300BLK both super sonic and subsonic loads, it is accurate to very effective distances especially in defensive carbine type rifles (400m) and can be very effective SBR’d. The round has a lot of potential and can be cost effective using already available components with minor modification to produce loads. My accuracy our of a 18″ SS Wilson Combat barreled AR was about 3/4″ at 108 yards with Horandy 110gr. Shots were taken prone off a Grip-Pod systems forward grip bi-pod and with an inexpensive 7x scope.

300BLK performs