4 Reasons .300 Blackout Is a Terrible Choice for Home Defense.

This is a guest post by Andrew Betts300 blackot

Okay, so it isn’t terrible exactly. Not in the sense that leaving a bottle of lotion on the coffee table and playing “Goodbye Horses” is a terrible way to impress a date, but it also isn’t what most of the breathless fanbois are fainting over, either. A big part of the attraction to having .300 Blackout is to put a silencer on it and feel super operator pew-pewing subsonic ammo. There is no argument that shooting a quiet rifle is a lot of fun, but fun does not stop bad men from doing bad things and subsonic bullets don’t do a great job of stopping them, either.

It really should not come as any surprise that when you slow a bullet down to pistol velocity it produces a pistol like wound. Now, to be explicitly clear, this load is not intended for defense. It is designed to hunt hogs discretely so as not to spook cattle. It does that very well. It is the only .30 caliber bullet that I have seen which can expand at subsonic velocity. It cuts a respectable path through the gelatin for a .30 caliber pistol bullet, but let us be crystal clear: for all intents and purposes, that is a pistol bullet.

In this perspective, a rifle loaded with subsonic .300 Blackout may as well be a pistol caliber carbine. PCCs may seem like a good idea at first glance, but when you get down to brass tacks they offer all of the disadvantages of a rifle (too large to conceal or carry conveniently and not easily operated with one hand) with the primary disadvantage of a pistol (weak ammunition). Not only does subsonic ammunition perform far more poorly in tissue, it also gives up one of the other primary advantages of a rifle: the ability to penetrate soft body armor.

Crooks are wearing body armor more frequently when committing home invasions and soft armor can be found in many pawn shops or online for less than you might think. It may not be a high probability, but the point isn’t that you must be able to penetrate armor. The point is that if you are going to choose a rifle sized weapon, you ought to use ammunition that can do rifle sized work. What about supersonic .300 Blackout, you say? It is absolutely true that supersonic .300 Blackout is every bit as effective as other intermediate rifle cartridges such as 5.56mm or 7.62x39mm.

You can see that it absolutely does a fantastic job, even coming out of an 8” barrel. It offers good penetration, expansion, and a respectable stretch cavity. In that regard, there is nothing necessarily wrong with .300 Blackout. At least, if you only consider the technical ability of the cartridge without considering cost. If you are looking to purchase a home defense rifle, .300 Blackout may not be a terrible choice, so long as you use full power ammunition. But if you are one of the many folks considering converting one of your 5.56mm rifles to .300 Blackout, it makes somewhat less sense. Supersonic .300 Blackout does nothing that supersonic 5.56mm, 7.62x39mm, 6.8mm, or 5.45mm can’t do and subsonic .300 Blackout is a poor choice for defense. While ammunition is becoming more widely available, there is nowhere near the selection and availability as there is for .223 Rem or 5.56x45mm.

Perhaps one of the most sobering problems with .300 Blackout is the ability to chamber in a .223 or 5.56mm barrel. While the bullet is obviously much larger, the parent case is 5.56mm so it will fit into the chamber. The bolt won’t close on a .300 Blackout round if it is closed slowly, but if the round has low neck tension, the momentum of the bolt carrier can force the bullet back into the case, allowing the bolt to close and lock. Remember, one of the main selling points of the .300 Blackout is that all of the parts are the same as your 5.56mm rifle, except for the barrel. Obviously the results of firing a round in this manner would be catastrophic. This presents little problem if you do not already own a 5.56mm rifle, but it seems fair to wager that the majority of prospective .300 Blackout owners also own AR-15 type rifles chambered in 5.56mm.

Someone once told me that .300 Blackout is the most convenient way to shoot 7.62x39mm in an AR type rifle. That is probably the most succinct way to sum up what .300 Blackout is. 7.62x39mm is a respectable cartridge and so is .300 Blackout… when it is loaded to supersonic velocity. While neither are well suited for long range shooting, they are more than adequate at close to medium range. The problem is that there are quite a few folks out there that just cannot seem to understand that a rifle bullet that is no longer moving at 2,000 fps, give or take, is not really much of a rifle bullet any more. To be fair, .300 Blackout is not actually terrible in its own right, it is just that the primary purpose for having one is to shoot subsonic ammunition and subsonic ammunition really is terrible for defense.


Andrew Betts served with the Arizona National Guard for over 12 years, including a tour to Afghanistan. Visit his YouTube Channel for more great shooting information.


  1. Enzo da Modena says:

    The .300 ACC Blackout is a very nice caliber if you are a reloader because it offers a huge variety of loads from very light and fast bullets to really heavy and slow ones.

    It’s also a very simple matter converting a standard AR-15 to shoot Blackout, you only need a new barrel.

    I use the Finnish powder “Vihtavuori N110” (which is one of the very few I can find in Italy suitable for this caliber) and it needs pretty much the same loads as the .357 Magnum for the same bullet weight.

    But other than a very “fun round” to toy with, is pretty pointless.

  2. Hey guess what, 300BLK comes in supersonic loads. Derp.

  3. Tom Dartsmuth says:

    Let me see if I understand this correctly. 300BLK does subsonic exceedingly well, supersonic as well as other intermediate rifle cartridges, without the blinding, ear bleed inducing muzzle blast, all in a package the size of a 9mm sub gun. The down side being it is a bit more expensive to shoot and less choices in factory ammo. I think I just found my new HD gun, thanks.

  4. Main problem – article title is not what article body states

    There are supposed to be 4 problems. These supposed problems are
    #1 subsonic rounds not very effective
    #2 supersonic ammo expensive
    #3 risk of accidentally chambering other rounds
    #4 Cartridges with ballistic performance similar to the 7.62×39 make poor long range weapons.

    The arguments are unrelated to the basic premise the title espouses.

    Article freely admits the 300 Blackout supersonic are effective defensive rounds, but subsonic rounds are not very effective. This does not detract anything from the effectiveness of the 300 blackout. You can’t criticize the effectiveness of a CHAMBERING by selecting ammo designed for purpose A and pointing out it is ineffective for purpose B. You might as well also write an article that 12 gauge is terrible for duck hunting because slugs are ineffective at taking flying ducks, while admitting that standard duck ammo works just fine.

    Article states 300 blackout supersonic ammo is expensive. Cost is not relevant to effectiveness. Had you argued there are cheaper choices, that’s fine. However, cost of ammo is irrelevant to effectiveness, and article is about effectiveness. Bling H20 bottled water runs $40 a bottle. It would be uneconomical to put out a fire using this water. However, the water would be as effective as any other water, economics doesn’t change effectiveness.

    Article’s third point is a supposed safety risk of mischambering a 300 round in another rifle. Yes and how does this make 300 blk ineffective for home defense. Let’s take this at probably the intended value – 300 is ‘unsafe’. Well, then that makes it an unwise choice not an ineffective choice. However I challenge the basic concept that rifle A is unsafe because you might take ammo from rifle A and try and put it in rifle B and that is bad. Well, that’s pretty much a problem every gun in existence has.

    Article’s concluding comment is 300 blk is not a great cartridge for long range shooting. If true, so what? Only relevant if long range shooting is a necessity for home defense. Even the biggest house does not have ‘long range’ distances inside of it.

    Is this article a joke?

    • Your critical reason is refreshing sir. Thank you.

    • Sgt USMC says:

      You completely “rekt” the writer.

    • Please don’t confuse the author with all of your logic and facts.


    • RE: Andrew, Be still me beating heart. It’s not often I get to see so much logic and coherent writing in the firearm community.

      Also, the article claims that “[.300 Blackout] is designed to hunt hogs discretely so as not to spook cattle” LOL, so the author thinks somebody was hunting hogs and spooked some cattle and so said “Gee, I should do something about this” and then went home and invented the .300 blk? That is not at ALL how this cartridge was developed. Some very cursory research into the round will reveal it’s history:
      and most of all http://www.thetruthaboutguns.com/2011/07/foghorn/ammunition-review-300-aac-blackout/ , particularily the primary requirements for the cartridge: “These were our original requirements for this caliber: Muzzle energy has to equal or exceed the AK-47. .30 Caliber projectile. Use unmodified 30 round magazines to full capacity. Use unmodified AR-15/M-16/M-4 bolt. Gas impingement system. Shoot super and subsonic. And one thing that was nice, but was not a ‘deal killer’, was non-adjustable gas system. Cycle all four ways – subsonic suppressed and unsuppressed, and supersonic suppressed and unsuppressed.”

    • I’ll probably get some type of flack over my comments here, but here it goes. Logic dose not stop the intruder(s). What % of times do the perpetrators come in pairs, or more? As far as sound, what the hell you talking about? Is everyone going to be wearing some type of ear protection when TSHTF in your home? Answer, NO NO NO. With that said, I use my 300 Blackout suppressed with suppressed 220 gr. bullets. I also have a flashlight and (Red) laser attached to use if necessary. This system runs perfect, and if more shots are necessary to STOP the threat(s), I can do so, without losing my balance from losing my hearing, from using an AK, 5.56 or shotgun etc. inside a home or garage. Even if they are wearing some type of bullet proof vest, placement of a couple of more rounds should do the trick. Just cause they wear a vest doesn’t mean the rounds you hit them with won’t breat a few bones or bruise the chest, or even stop the heart. They determine when you stop shooting. They stop, you stop (and reload if necessary). They start again, you start again. Sounds to me, that to many wanna be’s have been playing way to many video games. Real rehearsals, gets you real results in the real world.

    • great reply andrew
      one contradiction after another in the original article. pretty useless waste of cyberspace. But oh well—-everyone has an opinion and the other thing. I personally like the 300 blk. In the last 2 weeks I have taken 5 destructive beavers in my pond. 40 pounders with just suppressed 150 grain full metal jacket bullets that I got cheap in bulk and shoot just because they are cheap and accurate. I only have the head in the water to aim for and the wounds are devastating (some are follow-up abdominal shots).. these are out to 50 yds. lets see a 150 grain at 1050 fps. that exceeds a 9mm factory load for 147 gr.. The reason the article is a waste of time is for every caliber you can come up with, there is a more powerful and maybe more accurate round. Its a no win situation.
      Methinks this guy just likes to see his stuff in print. Also I REALLY doubt that burglars are wearing body armor I’d like to see where that stat comes from. My home defense gun is a 9mm. Lets see—- that has been around for how many years ?

  5. All the arm chair editors are on board I see. The title is exactly what the author wrote about… The overall downside of the 300 blk. The article is spot on. I jumped on the band wagon because I like weird cartridges and cans. But after trying to find a use for the blackout I just decided that I’m as well off with a handgun cartridge as a 300 sub load. Think a 230 grain 45 vs a 220 grain blackout moving about the same speed= same baseline performance. The advantage of the more aerodynamic 300 is mitigated by the fact rifle bullets don’t expand at 300 velocities and the handgun bullets do. I shot about a hundred hogs with the 300 subsonics, it’s not supèr impressive. It’s now relegated to quietly popping vermin off my deck late at night.

    • Popping vermin or plinking quietly off my deck late at night, and with the switch of a magazine having AK rifle range and stopping power, without any other changes to the gun or gas system. How exactly is this the same as your handgun? Did you use any of the expanding sub-sonic hunting rounds like those offered by Lehigh Defence and others? Those have been proven to be far superior to hand-gun terminal ballistics?

  6. Jeffrey Kent says:

    .300 Black is the perfect home defense cartridge especially from an AR-15.
    If your using a 9″ upper with a suppressor you have a weapon that is compact, quiet, and high capacity. Running any subsonic ammunition, you will be putting out more energy than a MP5-SD which shoots 9mm. I don’t think i need to talk about the success of an MP5.
    So if i can have a gun that’s similar in size as a MP5 but putting out the energy of a .45 acp while maintaining around the same decibel level, then i think you have a very effective PDW.
    Keep in mind the .300 Black was not designed for hunting game, it was not designed for long range target shooting, which is why it lacks abilities in these areas. .300 Black was designed for a very specific purpose.
    When supersonic it competes very well with 7.62×39, when subsonic and suppressed, it outshines the MP5-SD.
    Please don’t ever compare the .300 Black to a pistol or every say you might as well use a pistol, because i can guarantee you if you were in the woods, or at home with a pistol against someone with a .300 Black, you would lay your shit down.

    These are just my views and opinions, thanks..

  7. Find a better performing round for an SBR. Add to that the fact that you can switch between subs and super with a mag change and you have a nice little versatile powerful gun perfect for CQB. That’s basically what it was designed for.

    This auther seems to have come sorta agenda

  8. Jeffrey Kent says:

    I just don’t understand why the.300 black wouldn’t be an excellent choice for a pdw. Like I said, the mp5 is a very successful man stopper, and it shoots 9mm. So at its heaviest at 147gr. It’s less powerful but yet so effective. So I really think as long as you pick the right subsonic bullet for .300 black it will be very effective. Even at the very least, no man can handle 30 rounds of any caliber.

  9. Supress and shoot supers for HD

    110gr TTSX Blacktips.


    To impress friends shoot subs.


    70 gr TTSX in 5.56
    95 gr TTSX in 6.8 spc
    100 gr TTSX IN 6.5 Grendel

    All excellent supressed for HD as well, no Duds in any of these 4 calibers.

    • I definitely agree with your recommendation and I personally like the TTSX .Have you had a chance to test the Lehigh Defense 300 AAC Blackout/Whisper 108gr Controlled Fracturing Ammo -or- the Controlled Chaos ? Both are great rounds .

  10. 1911 holds 8 rounds.
    Ar15 300 holds 30 rounds.
    See the difference?
    ya I know the old wimpy 45acp has no “stopping power” ??

    Truth Is Both will end lives.

    Can’t belive I read this biased garbage.

    Ever shot in a house? Ever thought about over penetration ? You for sure need to think this through a bit more.

    Jump out of bed, Shoot your pistol in a house and no ear protection….let me know what you learned. Better yet don’t.
    Go take a good hd class.

    ill stick to 300 acc subs and suppressed for hd, and I stake my life on it.
    Because people smarter than me have trained me well.

    • “1911 holds 8 rounds.” True, but an FNX-45 holds 16. “Ar15 300 holds 30 rounds.” It can, but it can also hold 40, 60, or 100. Magazine capacity is really not a correlated to caliber, and thus should not be a consideration when choosing a caliber. It’s more of a platform and magazine question.

  11. Just one question to the author of this article… when you hear your door kicked in, or a window busted in by an intruder, would you rather have a subsonic rifle with 30 rounds ( that won’t blow out your ear drums by shooting in a hallway) or a pistol with 10-15 rounds or even a shotgun with 6 rounds that will cause permanent hearing loss. A few hundred dollars more in gun choice and Ammo seems worth it to me. Just saying…

    • I wouldn’t trust my or my family’s lives to subsonic ammo. There is a good chance you will experience cycling issues. I have had my ear plugs fall out many times and had to shoot pistols, rifles and shotguns (not to mention explosive charges) indoors. Yes your ears will ring, but this is about life and death. Much better to shoot standard ammo and be alive.

      • Chris Erickson says:

        Lol. I don’t care what gun/round you are running, you make it sound like you would buy a blackout and stash it in the closet without ever shooting it to make sure it works. I would not do that with any firearm. If subsonic ammunition was unreliable, then I guess we better call HK and tell them that the past several decades of success with the mp5 is a myth. The issue with subsonic rounds in an ar platform is that the average ar is overgassed from the get go, resulting in timing issues between bolt action time and magazine spring recovery. Build a blackout, install an adjustable gas block. Tune until it will cycle subs properly, and you are good to go. Note that the blackout was designed to work sub and super, both supressed and unsupressed.

  12. One more to pile on some very good comments above. Nothing prevents you from loading the first mag with say 3, 5, 8 rounds of subsonic and the rest with super sonic. Our a mag of sub and another with super. Point is you have options.
    Sbr with suppressor, very handy indoors.
    With 556, even suppressed, good luck shooting indoors.

  13. can I use my Gemtech. 45 suprressor on my 300 blackout mcx Rifle? don’t want the suppressor to fail. Gemtech said, ought to be fine

  14. This is no different than many other attacks on the 300 AAC. What all seem to ignore however is what the cartridge was intended for, and that is of course short barrels.

    Shoot a 5.56 and a 300 AAC out of a 8″ barrel and the results speak for themselves. The blackout maintains most of its velocity (and therefore energy), but the 5.56 loses a very large portion in addition to a concussive muzzle blast that would rupture your eardrums if fired indoors without earpro.

  15. Nathaniel Watson says:

    So you pick the weakest loaded 300 AAC out as you belittle the fact if it stops a wild bore it will defiantly stop a dude to call it a crappy pistol. Touch on conceal ability in a post that was supposed to talk a home defense in which concealing the gun is a non issue. and then suggest a common bad guy will be wearing plates. lol this should be titled “I don’t like the round because its popular so Im going to think of ANY crazy scenario to prove my bias” I laughed during the whole read lol thank you for that it feels good to have a hearty laugh.

  16. Stephen S Schindler says:

    It’s funny, as I read this article I was thinking more and more, “either this guy doesn’t know what he’s talking about, or I have read tons of bad information”. Thankfully, almost all of the comments reinforced my beliefs. It’s perfect for suppressed SBR and CQB (and how exactly is CQB any different than home defense?), PLUS you can have mid-range rifle performance in a heartbeat. I am the referenced guy that had an AR 556 and thought 300 BO was a good way to make it a home defense weapon, because since buying it, I have zero use for it in 556 other than range time, and I sure as well don’t want to shoot it in my house and risk killing neighbors with an errant shot. For ,<$300 for a complete 300BO upper (minus BCG), I have to rifles that can fill almost any need I will be faced with (I don't hunt).

  17. Stephen S Schindler says:

    Oh, and it’s funny that there is a link for an article titled “6 Reasons That a .300 Blackout AR Is the Perfect Home Defense Gun” at the bottom of this article at the time I am reading it :-)

  18. Yeah, I read this article and though.. WOW, has this guy ever shot a firearm in a dry-walled enclosure? After your first shot, dont expect to be accurate or feeling well. Its deafening. Ear’s and sight are compromised. The only solution is a subsonic ammo for indoors shooting. in comes the .208+ gr .300blk. without a CAN it has a lower DB reading than .45cal. with one, its quiet… Very quite.

    I believe that a .300blk with 8-10″ barrel with suppressor on it is the best PWD firearm a civilian can have.

    There is only 1 better firearm for home defense and that is my SBR AR-22 with my sparrow can on it. Unless someone see’s me or closer than 8 ft. they wont even know I am shooting at them.. until they are shot.. Oh, but wait. The whole premises of more people are wearing body armor now days defeats the .22 dosnt it? or … DOES IT? This is another area I have a problem with in this article. Like many people it seems he believes you can compensate for shot placement by increasing caliber size. FYI I can place a subsonic .22lr suppressed round where I want to. its not hard to say. ‘HEAD SHOT/CROTCH SHOT/HAND SHOT/ FOOT SHOOT/KNEE SHOT with a firearm that has no recoil and no concussion impact on my senses. Just an FYI… SHOT PLACEMENT > compensating for something ;)

    FYI i do own a gun store. http://www.mametactical.com so I kinda do this stuff..

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