300 Blackout

An email question:
Fixin to build a new AR, (my addiction is getting the best of me!). Thinking about a 300 Blackout. Other than having to stock up on a more expensive ammo, what are the pros and cons in your opinion? Just wanting a caliber with a little more thump for these big Georgia wild hogs.

My answer:
I have never owned one, shot one, or even seen one so I can’t give you any kind of opinion at all.
How about I post the question and let those that know answer?


I can’t answer a question that I know absolutely nothing about so I’m going to leave it up to you folks. Help the man out via the comments if you will, please.

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33 Responses to 300 Blackout

  1. J says:

    Subsonic with a can. Great Fun!

  2. jimmie mason says:

    Love mine. 2 ar’s and a handi rifle. If you reload its cheap to shoot. I reload and cast so I can make mine real cheap. Don’t hunt but from other people I talk to its great for deer, not sure on hogs.

  3. West says:

    Just build yourself an upper. Lower and mags (.223) should work fine.

  4. Cabron says:

    Do it. I love my 300 blk. If you reload ammo is not too bad. You can easily convert 223 to 300 blk.

  5. Woody says:

    Here’s a forum concerning Georgia hog hunting with the question you asked. Hope it’s not your question. http://forum.gon.com/showthread.php?t=718668
    Also check out the forums on AR15.com.

  6. Brian S. says:

    I’ve got several. Very versatile round. Brass is easily made from 5.56/,223 (although it’s readily available from Palmetto). Super sonic loads only use roughly 20 grains of powder, sub sonics about 11 grains. (You can load 600+ sub sonics with 1 pound of powder). It’s very accurate. You can use your existing 5.56 magazines and bolt carrier group so if you want to test drive one on the cheap, you can simply buy a barreled upper assembly then build out a complete rifle piecemeal if you like it.

  7. Sconsin Rick says:

    The 277 wolverine is a much better similar option in the Ar15 platform. Much cheaper if you load your own . There are 2 other sources for loaded ammo if you don’t. It is a similar concept to the black out but with higher velocity .227 bullets. flatter trajectory. look up MDWS. there are also several other wildcat rounds if you load your own that will put the hurt on critters of all sizes. think building ARs is an addiction, wait till you start building Wildcat ARs. its never ending. many of them are near the performance of full sized AR10 sized cartridges. 22 Hellcat > 22-250, 257 Bobcat = 25-06, 7mm Valkyrie =7mm-08. and several others that I don’t have yet all in the AR15 platform.

  8. Chuckles says:

    If you are putting it in an AR, 7.62*39 would be a better choice. Realize you are shooting essentially a 30-30. If you are using standard barrel length the *39 will likely go faster. If you are going subsonic, 9mm is about the same but cheaper. If using a *39 w SBR u will want a can. Price per box, best I’ve seen at Wallyworld is 15.98 for .300bo. The same place sells *39 for 9.99/40. You do have to buy different magazines, and you will need an additional bcg or just a different bolt to swap out, and an enhanced firing pin but the *39 gun has come a long way. Make sure you have m4 feed ramps. Just my two cents.

    • =T.W.= says:

      ^^ I concur.

      I like the idea of a pistol caliber carbine like the Camp 9. Or my .357 Trapper.

  9. Leigh says:

    I don’t own one myself, but have seen one very problematic issue. Apparently, certain loadings of 300 BO/Whisper can chamber into a standard 5.56 barrel. The bolts are the same between the two, so that won’t stop it from going into battery if the OAL of the 300 cartridge is short enough.


    Personally, if I were to do a caliber other than 5.56 in an AR, it would be a 6.5 Grendel or a 6.8 SPC. The ballistics are way better than the stubby .300 .

    This post has charts that compare trajectory , velocity , and energy of common AR chamberings.


    Whitehall, NY

  10. Christopher Look says:

    Having shot and owned both, I prefer the 300 blackout. My question to you would be, do you reload? One reason I chose blackout is that the casing is just a 556 case cut off at the shoulder and formed. Most of my brass is 556 left at the range. Also, the 30 caliber bullet is the most popular in the world. That being said, components will, virtually, always be available. It also is a more powerful cartridge. Not by a whole lot, but still more. It will also carry that energy better at range due to the bullet weight. I’m sure there will be responses to this quoting kinetic energies. But remember, kinetic energy is only part of the equation. How efficiently the bullet dumps that energy into the target is very important.
    The 300 blackout is a cartridge that the more I shoot, the more I like it.
    I also recommend reading a paper called “taking back the infantry half kilometer.” Just Google the title and it will show up. It’s an excellent read, was written by an Army Major in 2009 addressing shortcomings of the 556, and current tactics and structure in general.

  11. Paraclete says:

    Most everything concerning this build will most certainly be expensive.
    Due to the fact that it’s an “odd ball” variant.
    But what you aught to consider is this….In the day, when things fall
    apart, you know, SHTF… not only will your ammo be scarce, but your
    much needed spare parts will be even harder to find. If you must build
    this…you had better store up at least “three” of every spare part you can.
    Then lay in all the components needed for reloading “thousands” of rounds.
    All this is said, of course, “IF” you’ll be depending upon this firearm in the
    SHTF days ahead…which by the way, are fast approaching.
    Myself, I would invest all that money in a system which would yield easier
    to find parts and caliber ammo. Such as a PTR 91 in .308
    Most, if not all, parts which will be needed in the days ahead can be easily
    found as well as the ammo, as compared to what you’re presently considering.
    Hope this has given you reason for thought.
    Don’t forget, the AR platform defecates where it eats…
    Hence, parts will wear out more often.

    • Chris says:

      actually its comparable in price to building a 556 AR. it was designed to use as many standard ar parts as possible it only requires a barrel change. the ammo is slightly more expensive unless you reload.

  12. James says:

    I also suffer from the “build addiction”and did a .300 blackout.First off,if you have a AR in 5.56 a change to blackout can be as simple as a barrel swap and the ammunition.The .300 uses the same mags/BCG/ect.

    What are your goals with the cartridge?You can go up to 220 grain or so and lower roughly around 90 depending on your goals/hunting/longer range target ect.Good quality 5.56 brass can be shortened/sized ect. and then loaded with your .300 bullet of choice.For whatever reason a lot of 5.56 shooters using decent brass leave in recycle buckets at ranges(thanks folks)so can help a smidgeon with costs.

    I have not done so but the .300 works well as a suppressed cartridge in folks who shoot with cans.

    A lot of folks do this to hunt with as some states do not allow the use of 5.56 as believed not enough cartridge to hunt with(a whole argument right there).My friend has hunted and bagged deer with his and really likes the round,not sure his bullet characteristics he loaded.As for hog hunting have never done it so not sure what the best all around round for them may be.

    I thought was going to do just a barrel swap,should have known better!I built with FN barrel at 16” but may change that,works well but so far have not done longer then 200 yards with rifle so still learning about it,am happy with the choice.

    I will say no matter what,dedicate some mags to the .300 and have clearly marked,same with the rilfe,I personally have a AR in both 5.56 and .300 that in most ways look like twins,you can see the problem here if you are not paying attention,though hope if shooting you are already paying sharp attention.

    So,still just getting to know the little guy but so far am really enjoying it,depending on your goals may be a good choice,or,you may go with something else that more suits your goal,either way,have fun!

  13. obsessivecompulsivehater says:

    My buddy has one. I could not shoot that sucker at 200yds to save my soul. He loves it, but doesnt hunt it fwiw. To much kick for my taste. And I shoot a 45/70 lever.

  14. beaver67 says:

    My buddy has one with a fully suppressed barrel, I think it is a Daniel Defense, he shoots subsonic ammo and regularly kills multiple hogs when he goes out. He has a thermal scope on top of it too.

  15. Free Citizen says:

    If you insist on an AR platform, go to an AR-10 in 308. Ammo is plentiful. For hogs, here in Oklahoma I personally use 30/06, then I can use either my Remington 700 or my M-1 Garand. There again, ammo is plentiful and common. I also like 45/70 in my rolling block. I don’t have anything to do with the AR. I’m an 11B Vietnam vet from 67-68. Our weapon of choice was the M14. ‘Nuf said. You also need to learn to handload and stock up on components that are common with all you shoot. You don’t have to be concerned with availability that way. Good luck.

  16. rickylizardo says:

    I’ve been shooting a.300 BAC for about two years now, and compare it to the .762X39. If you reload, you can make .300 brass out of .223 cases, I save the brass with damaged necks for this. I haven’t had a chance to work up to max loads, but have had good luck with 150 and 168 g Hornady bullets at 80% max load. Unfortunately, no hogs to practice on out in flyover country but they do considerable damage to old personal electronics…

  17. riverrider says:

    built one, sold it. built another, sold it. 300blk is designed to fire from a seven inch barrel with a suppressor on the end. if that’s what you have in mind go for it. if you’re thinking 16 inch nfa legal barrel i think you will be disappointed. in lighter bullets the drop isn’t too bad but too much for my liking and heavy 220 grain hog hunting bullets are subsonic and drop like a rock at 50 to 100 yards. that has been my experience. it is perfect for house clearing if that’s your thing…i looked at 6.8 and decided against that one too, it didn’t live up to the hype. if you run 5.56/223 77 grain razor core or similar in a 1/7 twist barrel and hit your mark i think the hog will go down. be aware 77gr doesn’t stabilize well out of some 1/9 twist barrels. the little 223/556 will do damn near everything you ask of it if you use the right ammo and do your part.

  18. ChuckN says:

    .300 has a pretty good punch. You will lose a bit of range though.
    I’ve found that 100-150m is about optimal for my set ups (H&R
    Handi and an AR). However, depending on your location
    the range shouldn’t be much of an issue. Recoil is pretty light,
    about on par with a Henry in .357.

    As far as ammo goes, I reload so price isn’t too bad. Since you have
    an AR already you can simply reform the 5.56 brass for .300.
    Play around with the bullets. For heavier game I like a heavier round
    nose, but a spire point may work better in you AR build. A good
    midweight round, say in the 160gr range, is probably all you need
    unless you got really big hogs, then maybe go heavier. Try different
    magazines, I’ve had better luck with cheap P-Mags than standard
    steel. This is especially true when I have round nose or a longer
    180gr boat tail.

  19. PHIL (impala458;) says:

    Hogs? .458SOCOM -there is no substitute. A semi-auto w/ .45-70 ballistics and you only need a
    complete upper- utilizes standard unmodified ar-15 lower receiver & magazines…

  20. MTHead says:

    Blackout is a lot of fun. if you reload its a great round. it will shoot any 30 cal. bullet from a 85gr. to 240gr.,(with the right twist rate.) super-sonic to sub-sonic. If your looking for range, its not the round. What we’ve found is its best suited when you need a short barrel, short range, hard thumper, suppressed.
    It’s a perfect police gun. 8″ barrel, 4.5″ Omega9k suppressor. total front end package at 12.5″. light, easy to get in and out of car with. loaded with 110gr. Vmax loads. it’s 100yrd killer. humans to hogs!
    If your building, buy a new stripped lower, pistol buttstock, upper, 8″ barrel, key mode handguard,(I like CMMG, sbn,. for humid climates.) sig brace, or any one of the many paddle braces out there.
    Soon it will be going everywhere with you!

  21. Boone says:

    Have one scoped AR, 16″ 300 AAC as an intermediate rifle and a 7.5″ AR .300 AAC pistol. It’s just really a fun round and cheap to shoot of you reload. Never hunted with it but there are plenty of testaments as to what it can do on game up to and including deer within about 200/250 yards with the right load. AR parts fully interchange with the .223, careful you don’t intermingle ammunition between the two. Pay for the tax stamp and a silencer opens up yet another world for the 300.

  22. Dave says:

    How about instead go forth and look on Guns America etc. Then find yourself a good bolt action in either 257 Roberts or 308 & you are good to go. You will probably save money and hit things in the long run.

    I will be glad when the AR Fever runs its course. As you can see I am no fan of the AR Systems. The way I see it. A good man with a good bolt is just as good at hunting as the AR Man. Unless you want to spray and pray or want to set down a base of fire.

  23. Cody says:

    6.5 Grendel will hammer hogs just fine, ammo and parts for a build are reasonable, shoots flat. Or just use chunkier 5.56 in the 70 grain plus range, and shoot straight.

  24. =T. Wrangler= says:

    Since the AR exploded in popularity there have been dozens of cartridges adapted to the platform.
    This may be due to the perceived limitations of the 5.56 and/or the specs of early rifles.
    Modularity of ARs invites tinkering- a host of combinations are possible, limited only by action length and bolt dimensions.

    About the time I got my AR in X39 dialed in, .300 AAC (BLK) was standardized by SAAMI.
    Its main advantage over the X39 is that it runs with standard 5.56 bolt and mags. Ballistics essentially duplicate the hugely successful Russian carbine round. This is largely offset by the cost of specialty ammunition. Subsonic loads are useful with suppressors on SBR’s and AR pistols (if one can afford them.)

    The X39 is a good general purpose carbine round, equivalent to the well respected .30-30 Win.
    And, the price is right.
    An AR in X39 will require dedicated bolt and mags. but little else to run smoothly.

    Have fun tinkering!

  25. Eric in Florida says:

    I was considering the same thing and didn’t after looking at the ballistics. They have a considerable drop in elevation and impact energy starting at 75 yards.
    as a range toy I could see it being fun to try to hit at different ranges but for hunting I’d stick to something with better ballistics.
    Then again this is a opinion I don’t own one.

  26. TOR says:

    Pro- Comparible with 5.56 lowers and mags.
    Pro- Great for silencers and SBRs.

    Con- Oddball cartridge. Oddballs are such for a reason.
    Con- Pretty short range cartridge.

    Conclusion- Unless you are making an SBR and putting a can on it there is no advantage over either an AK-47 or a semi auto .308 like an AR-10 or a FAL. Both of which are common and much cheaper to shoot.

  27. Wm. Dwain Cleveland says:

    300 blackout is kinda iffy for feral pig. Been known to bounce off the skull and not put them out. P.O.’d pig of any size is not good. DPMS – LR308 is the choice of a lot of folks down around Macon, Ga. I know at least half a dozen guys that swapped out a 300 for a 308. That’s my coice as well.

  28. M. Sage says:

    Pros: Suppressed with the subsonic ammo are quiet as hell!
    Short (>16″) barrel performance does not suffer.

    Cons: May insert .300 BLK magazine in 5.56 rifle and blow it up.
    Not significantly improved terminal performance over 5.56 (for hogs, bonded SP like Federal Fusion MSR or copper solids like Hornady GMX or Barnes will give you the penetration you’re after, and so will military surplus stuff like M855 or the Mk318 SOST if you can still find that stuff.)
    Expensive compared to 5.56.
    Yet another caliber to stock.

    My suggestion: Go shoot competitively. Buy a shotgun and do 3 gun matches and you’ll be a stud in no time. Karamojo Bell’s favorite caliber for killing elephants was 7×57 Mauser AKA .275 Rigsby. Not a terribly powerful caliber. He even killed one with a .22 just to prove that shot placement mattered.

    5.56 will get the job done, so long as you do yours.

    FWIW, after two years of 3 gun, I straight up dropped a whitetail doe at a dead run at 100 yards with one round from a 5.56 AR15, after I made a 20 yard sprint to where I could make a shot.

  29. bobdog says:

    If a larger calliber in an AR platform is what you want, why wouldn’t you start with .308 Winchester?

    Why would you limit yourself to 200 yard effective range?

    My benchrest rifle is 6mm PPC, and I can tell you that wildcat cartridges get expensive. It shoots well under a quarter minute of angle, and I absolutely love it, but brass alone costs me $2.00 a round.

    My hunter class rifle is a single shot Remington Custom Shop 40X in .308 Winchester, and it shoots under a quarter minute of angle for a fraction of the cost with handloads, even with relatively expensive Lapua brass.

  30. Dan in Ohio says:

    If your not going to put a silencer/suppressor on it, DON’T BUY. It is the ballistic twin to the 7.62x39mm.
    Forget the hype. Buy a .308 cal AR-15, or an AK-47 (AKM) type rifle. Use these for more smack-down on hogs. They won’t know the difference.
    Best regards.
    Dan in Ohio.

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