Close range effectiveness: 5.56 NATO v. 300 blackout

.300blk by a fairly large margin. This is what it was designed for.

Given the choice I'd use 5.56/223. 300 BO was designed to be quiet with a suppressor. At best it still 100-150 fps short of 7.62X39. And 5.56 has proven to be the better than 7.62X39.

Balrog said:

Which would be more effective at close range out of AR 15 with 16" barrel? 556 NATO v. supersonic 300 BO.

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How close are we talking? 100 yards or 25 yards?
It really doesn’t matter, the 300 blk wins every time. Remember that a 300blk is about the same as an AK round when supersonic and about a 45acp when subsonic,

jmr40 said:

Given the choice I'd use 5.56/223. 300 BO was designed to be quiet with a suppressor. At best it still 100-150 fps short of 7.62X39. And 5.56 has proven to be the better than 7.62X39.

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is that so? In what aspect? Range and weight? Because in everything else the 7.62x39 wins, penetration, power, wound channel , retaining weight, at close range I believe the 7.62x39 wins

Cherry picking loads and shots taken I prefer a 556/223.

Actually..... personally id pretty much always take the 556. I was very disappointed in the performance I was getting from my blackouts, tho others have done quite a bit better.

If we're actually discussing x39 rounds with 125s at 2400 plus then I'd rather have that, But I never even came close with my blackouts.

For the most part the average 223/5.56 AR is more accurate than the average 300 BO, but at close range this is less of an advantage.

For either, close range effectiveness improves with ammo that will reliably give the right amount of expansion.

The 300 BO with 125 or 130 gr premium hunting ammo is pretty effective out to 100 yards.

The 223 with premium hunting ammo is also pretty effective.

In my opinion, the larger diameter and heavier 300 BO bullet has a better chance of still being effective even when things do not stack up as planned.

Effective on what? Depends on the bullet.

5.56 75gr TAP SBR 10.5"


300 110gr TAP Urban 8"


5.56 GMX TAP Barrier 16"


300 GMX TAP 16"

Can i get a picture of the damage/wound channel of a 300blk 150gr going 2070fps?


Pic of my reloads 300blk and 308 using the same hornady 150gr Interlock bullet

Balrog said:

Which would be more effective at close range out of AR 15 with 16" barrel? 556 NATO v. supersonic 300 BO.

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Suppressed 300blk, Unsuppressed 556. For all intents and purposes, 556 is more than enough due to ammo cost, if ammo price is not a factor then 300blk…

what im trying to say is that it’s purely personal preference, for close range both are awesome, one uses speed the other use mass to achieve the same thing.

Note: for a first/one gun only I recommend 556, then get a 8” 300blk suppressed once you get enough training.

I define effectiveness at close range as the ability of either round in the discussion to stop a threat immediately. Assuming hits are obtained where they need to be (which needs to happen with any round, BTW) I have never seen the 5.56 "fail". Assuming we are talking AR type rifles, they hold more than 1 round, so there is that. I have also used 5.56 on critters like deer and hogs, and the Hornady 75 gr BTHP has done a phenomenal job. As in, no tracking required. I have shot a couple of deer and 1 fox with 300 BLK- all ran on me.

Zerodefect said:

.300blk by a fairly large margin. This is what it was designed for.

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The part about the ballistic results is accurate - bigger bullet more mass more foot pounds, etc.

.300 BO wasn't "designed", it was copied from .300 Whisper. It was widely reported at the time AAC came out with it. Whisper was originally based on a 3 Gun work around in the 1980's to get AR15's into competition because of a rule the rifles had to be .30 caliber. When competitor's arrived with a wildcat, .30 bullet in a 5.56 case, they discovered the rules meant nothing and they weren't allowed to enter competition anyway.

Imagine a governing authority who disregards written rules and tramples all over the participant's interpretations. Gee, that never happens.

That only lasted a few years, and the AR15 was allowed in with 5.56, at which point it quickly dominated competition as it has less recoil and quicker, more accurate follow up shots. At that point .30 x 45 went back to the loading bench as a concept as nobody was going to shoot it by handloading it for competition. 5.56 was cheaper and available, plus has flatter shooting long range capabilities, works good for competition. IE, paper. JDJ worked with it as a subsonic for suppressed use in the 90's, long before AAC.

The first .30 x 45 was really designed to get around a rule meant to keep AR15's out of competition. It was discussed on forums then how AAC just changed a blueprint number and invented a name for it. As have dozens of other "new" cartridges introduced by every manufacturer. Common practice, yet we tend to gloss that over a bit while still aware of .223 vs 5.56, or .308 vs. 7.62, etc etc etc.

Ever hear of the .264 LBC? You might know it as the 6.5 Grendel. That's what kind of games the cartridge makers play.

FL-NC said:

I define effectiveness at close range as the ability of either round in the discussion to stop a threat immediately. Assuming hits are obtained where they need to be (which needs to happen with any round, BTW) I have never seen the 5.56 "fail".

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This.

5.56 M193 works. Period.

When I hear "close range," that's the same as "CQB" to me. Meaning: a max of 50-yds right down to contact/on-top-of-you distance.

Putting aside all the ambient "noise" about the Kyle Rittenhouse/Kenosha incident, the bare-bones ballistics of the three thugs he shot at or within contact distance clearly indicate that 55grn ball ammo works as a "close range" fight-stopper.

As far as the 300BLK goes, that cartridge only interests me in one very narrow, nichey format: heavy bullets sent subsonic and suppressed from an 9"/10" SBR (AR-platform). Close range there = home defense, i.e., going room-to-room.

Beyond that the 300 BLK doesn't really do anything for me as a hunting cartridge. I have other cartridge I prefer, as well as platforms.

556 by a good margin in my opinion when talking out of a 16” carbine.

I’m with others above when saying that the 300BLK only interests me in sub-10” barrels with supers or heavy subs as that is where it shines in efficiency of burn thus translating into greater effectiveness versus other cartridges in the same short barrels.

In a 16” carbine with supers 7.62x39 has significant advantages over the 300BLK (150-200fps advantage)

Tirod said:

The part about the ballistic results is accurate - bigger bullet more mass more foot pounds, etc.

.300 BO wasn't "designed", it was copied from .300 Whisper. It was widely reported at the time AAC came out with it. Whisper was originally based on a 3 Gun work around in the 1980's to get AR15's into competition because of a rule the rifles had to be .30 caliber. When competitor's arrived with a wildcat, .30 bullet in a 5.56 case, they discovered the rules meant nothing and they weren't allowed to enter competition anyway.

Imagine a governing authority who disregards written rules and tramples all over the participant's interpretations. Gee, that never happens.

That only lasted a few years, and the AR15 was allowed in with 5.56, at which point it quickly dominated competition as it has less recoil and quicker, more accurate follow up shots. At that point .30 x 45 went back to the loading bench as a concept as nobody was going to shoot it by handloading it for competition. 5.56 was cheaper and available, plus has flatter shooting long range capabilities, works good for competition. IE, paper. JDJ worked with it as a subsonic for suppressed use in the 90's, long before AAC.

The first .30 x 45 was really designed to get around a rule meant to keep AR15's out of competition. It was discussed on forums then how AAC just changed a blueprint number and invented a name for it. As have dozens of other "new" cartridges introduced by every manufacturer. Common practice, yet we tend to gloss that over a bit while still aware of .223 vs 5.56, or .308 vs. 7.62, etc etc etc.

Ever hear of the .264 LBC? You might know it as the 6.5 Grendel. That's what kind of games the cartridge makers play.

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AR-15 have always been allowed in 3-gun/multi-gun going back to the 90's when it really became a nation wide sport. 300 Whisper did not become a thing until the early/mid 1990's.

The only story with regard to 300 Whisper/Blackout and 3-gun competition I am aware of it that Horner in 2011 used 300 BO and a long barrel to make Major Power factor from an AR15 and win the 2011 USPSA Multi-gun Nationals in the Tactical division. Regular 556 cannot make Major Power factor even from a 20-inch barrel and it was a stretch for 300 BO hence the long barrel he used (IIRC he was pushing 155gr bullet to ~2100 fps). This gave him a scoring advantage while still allowing him to use the lighter AR-15 platform and reliable 30 rds magazines and that likely contributed to his win. Up until that point most competitor being score Major where using a 308 Win rifles like AR-10's, M-14(Clones) and FAL's but they usually competed in the Heavy Metal division because even scored Minor AR-15 dominated the Open, Tactical, and Limited division. No rules were bent, Horner just saw a way to get to the Major scoring advantage with an AR-15 plateform.

http://bulletin.accurateshooter.com...actical-optics-divison-at-multigun-nationals/

But Power Factor is a measure of recoil when you look at Kinetic Energy both cartridges are roughly the same ~1300 ft-lbs of muzzle energy from a 16-inch barrel. 300 BO has a momentum advantage (Power Factor) if you believe in that but 556 has a flatter trajectory. Due to its higher muzzle velocity and smaller caliber it will also penetrates armor better than 300 BO with the correct bullet.

As for 300 Whisper vs 300 Blackout. In a rare moment of sanity AAC/Remington actually made 300 BO an SAAMI cartridge opening it up to the entire market where SSK Industries was trying to make 300 Whisper a proprietary cartridge. A mistake Remington had made several times before. This move was likely due to work AAC/Remington was doing with the US military (as much as learning from previous mistakes) around the cartridge and since AAC/Remington was a SAAMI member company it made sense to push it through the SAAMI approval process. That simple fact is the biggest reason 300 BO became a commercial success and 300 Whisper has faded into obscurity.

Interestingly 300 BO became a SAAMI cartridge in 2011 and 300 Whisper had become a CIP (Europe's equivalent to SAAMI) cartridge in 2009, I have never figured out why SSK industries did not also make is a SAAMI cartridge at the same time but that let AAC/Remington do what they did and we now all argue about 300 Blackout, not 300 Whisper.

I love 300 BO but I use it almost exclusively as a suppressed gun shooting sub-sonic ammo.

sarduy said:

one uses speed the other use mass to achieve the same thing.

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That. Actual distance and the hardness of the target will come into play, of course.

I had more success with 125 grain supersonic blackout bullets on pigs than I did with 55 grain bullets out of a 223.

Ymmv.

LoonWulf said:

Cherry picking loads and shots taken I prefer a 556/223.

Actually..... personally id pretty much always take the 556. I was very disappointed in the performance I was getting from my blackouts, tho others have done quite a bit better.

If we're actually discussing x39 rounds with 125s at 2400 plus then I'd rather have that, But I never even came close with my blackouts.

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Did you ever take any game with the blackout or X39? I know you do a lot of hunting. I've shot deer with my X39 and coyotes with 223. The damage a 50 grain v-max does to a coyote at short range gives me a healthy respect for what the lil 223 can do. Humans are pretty lightly constructed.

someguy2800 said:

Did you ever take any game with the blackout or X39? I know you do a lot of hunting. I've shot deer with my X39 and coyotes with 223. The damage a 50 grain v-max does to a coyote at short range gives me a healthy respect for what the lil 223 can do. Humans are pretty lightly constructed.

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Ive taken axis and pigs with the x39 quite a bit, but mostly with late 90s Winchester softpoints, nothing with the newer stuff besides a couple small pigs.

Took few pigs with the aac, couple with 125 tnts, and a few with 245gr MBC hard cast.
I remember talking about it, and i THINK you were beating my best velocity by a couple hundred fps?

Ive killed alot more critters with the .223/555, and my opinion is that very few things are going to walk away from a 50-65gr bullet in the squishy bits.

I will just say there are probably good loads for both, and there are definitely not so good loads for both. There are bullets and loads that will act like a frangible varmint bullet in both, and their are bullets and loads that will offer deep penetration in both. I think in a 16" barrel the good loads from both would probably be similarly effective. In a short barrel the edge would go to the 300 blackout, its just more efficient.

Speaking of loads, I reload for blackout and 7.62x39 in 16" AR's.

Russian factory 7.62x39 in my gun over my crono are generally 2400 fps or so.
Handloads I've tested with powders other than CFE BLK max out around 2500 fps with a 125.
Handloads with a max load of CFE BLK go just over 2600. (I think hodgden has since lowered the max charge weight a bit)

Handloads in 300 blackout for me with 296 max out at 2400 fps with a 125 with excellent accuracy.
Handloads with a max charge of Lil Gun went 2500 fps with a 125 but displayed dangerous overpressure at very cold temps so I stopped using lil gun.

My 7.62x39 seams to be par for the course with others but my blackout barrel seams to be very fast compared to some others. Mine is kind of weird being a 1:8 twist and carbine gas instead of the typical 1:7 and pistol gas, so maybe that's what makes the difference.