About the Author

Kilgore & Call
Richard Kilgore and Jake Call have been writing on and off for Military.com for many years now. You can reach them at BreachBangClear.com or follow them on Instagram at @breachbangclear or Tumblr at http://the-mad-duo.tumblr.com/.
  • Lance

    Both have good points and advantage and disadvantages. If your looking to shoot unsuppressed and out to over 100 yards nothing wrong with 5.56mm. Or if you want suppress fire and shooting cqb .300 BLK is awesome.

    Im growing tired of constant fighting and comparing with people always saying new is btter or this new caliber sucks. Instead of comparing find out for yourself if you like that caliber.

  • R3D R3IGN S1X

    ****, I’d like to give it a try!

  • Bman

    I’ve heard loads of good things about the 300 blackout, lots of good and bad things about the 5.56 and mixed good and bad things about 6.8 and 6.5. In law enforcement, 5.56 is most common but really about as much .223 rifles are out there as 5.56 which isnt a huge problem but if the 5.56 negatives are true, then they will be more evident in the .223’s. I have met guys who have put several .223s in a dudes center mass and they are alive and walking today but they admit the threat stopped immediately. P90’s with 5.7mm or whatever it uses had very bad “stopping power” (for lack of a better term) with the nearby big city SWAT team and they dumped them for AR’s in .223 around the time that the entire agency got carbines. One incident, they put 13 5.7mm rounds in a heavy-set drug dealer’s center mass at close range and they remember him sitting upright on a curve in handcuff’s and asking, “what did you guys shoot me with?” I suspect they chose .223 over 5.56 because of the people screaming that they were militarizing themselves with the same weapon the military uses. I say let SOCOM, AMU and the Marines test each caliber against each other in different environments and see what has the most consistent performance. I bet 5.56 and 6.8 would be the go to since gun makers are already making swappable versions.

  • mos2111

    I concur Lance. In looking at these two rounds, I suggest looking at purpose first, then energy. Suppressed and SUBSONIC the .300 blk is awesome – especially in a bolt gun for silence. But the important thing to remember is this round is heavy and slow. Look at the energy on target delivered by the following rounds (you can do the calculations yourself here http://www.firearmexpertwitness.com/customguns/ca….
    .45 acp 230 gn @ 920fps = 432 ft lbs
    9mm 115 gn @1200 fps = 368 ft lbs
    .300 blk 290 gn @ 1000fps = 643 ft lbs
    5.56 55gn @ 3100 fps = 1173 ft lbs
    .308 175 gn @ 2900 fps = 5134 ft lbs
    .300 win mag 290gn @ 2900 fps = 5414 ft lbs
    These numbers dont show us anything about expansion, projectile weight retention or specific rounds “wounding mechanisms” such as fragmentation, ect; but they do show raw data that can be used to form an intelligent decision. After playing with the .300 blk a while ago, I moved on. It was crazy quiet through a .30 can with subsonics and works on a really short barrel and pistol gas system, but was pretty damn similar to having a .45 acp carbine in terms of energy… Its neat and Im glad there is industry support behind it, but it just never fit my needs for home defense or hunting or cost efficient range use.

  • mos2111

    The concept of stopping power is a misnomer at best. Here is some great info on “wounding ballistics” and some very good reading by individuals who are vetted and scientific in there approach. Facklers stuff should be a must read for all shooters.
    Enjoy. http://www.firearmstactical.com/wound.htm

  • Jay

    .300 blk is a lot of hype. The subsonic loading is really a good thing as it has a clear purpose and it is needed. The supersonic loadig doesn’t do anything the 70 years old AK round, with good bullets, doesn’t do.
    It’s funy to see the same people that bash the AK round talk about the .300blk like is the second coming.

    • Chris

      LOL you’ve missed the whole point of .300 blackout.
      It’s major advantage over the AK is that is doesn’t come out of the end of one.

  • Snakebymistake

    I have to agree. Americans are always in a hurry to reinvent the wheel. As far as I am concerned my .30/06, .308-7.62X51, and 7.62X 39 and 47R offer more of the old better. Actually my .58 Civil War Musket and .54 Sharps will leave a wider wound channel than most bullets today, they also have a tendency to blow apart an arm or leg bone, leaving a two inch gap in the bone. My .79 cal Brown Bess actually blows the biggest hole!!! Reminds me of a 12 guage slug ????

  • Daily Llama

    Not really a lot of hype, sorry you don’t understand it’s purpose. Me? I *love* the 7.62mm AK round!!! The tiny 5.56 is a wonderful, lightweight round – but generating pure ft/lbs of energy by the F=MxA equation. It still doesn’t create a “kill-shot” wound cavity every hit. Certainly w/o coming under the record-keeping of the BATFE for ownng “another rifle”, the 300 BLK gives civilan AR owners the closest firepower yet to the legendary AK-47 … with NOTHING except a barrel change. Same 5.56mm bolt / bolt carrier, same magazines, magazine capacity … etc. It’s probably – in hind-sight – what the M-16 *should* have been right from the get-go.

    I missed finding 2 big boars I hit with well-placed 5.56mm shots in ’10 and ’11. Wasn’t able to get a second round in them because they ran ….

    Hit a bigger boar than those two YET in late ’12 with my self-built .300 Blackout AR upper … and it dropped like a rock. BANG! It just fell over … on the spot.

    125gr FMJ – not even a JHP – approx. 2,600 fps thru a beautiful BHW polygon barrel. It went thru and, flipping the beast over, the exit wound stunned me! Must have bounced off of a bone, deformed, etc. because I could have put my fist in the hole.

    In the same brass as a standard MIL-spec 5.56, you get both supersonic and suppressed capabilities – with a minimum of 2X the mass of a 5.56 round – and almost a 40% larger wound cavity in either case. In close-in warfare – 15 – 80m – velocity isn’t the bonus that pure, ultimate, “one-timer” stopping power is.

    Walking thru a side-street in Kandahar, I’d take a SBR AK-47 over an M-4 / M-16 every second of every day!!!!!!! And live to tell about it!!!

    But the sub-sonic capabilities are what has miltary signifigance. As in, you can shoot some 300 BLKs while inside a hard-walled structure and not go deaf. Have heard completely unconfirmed rumors that special-ops AAC-suppressed HK 416s – with 220gr 300 Blackout rounds – were used to double-tap “Geronimo” …

    On White House recordings from the raid on ObL, you barely hear a “chuff!” with each round fired. Those were NOT regular 5.56mm NATO rounds! Nor even “suppressed” 5.56s. Supress a 5.56mm round so there’s barely a “pop” and you might as well just throw a handful at your target.