300 Blackout makes the most sense in an AR with a short barrel with a suppressor.

It allows the use of Supersonic loads interchangeably with Subsonic loads (that can be suppressed quite effectively compared to supersonic rounds).

For people who like heavier bullets than are available for 223/5.56, they get that from 300BO.

I assume the reason the 7.62x39 did not get that gig was that:

1) It would have required a different magazine configuration in an AR to make it work
2) No one did the same subsonic load development work that was done on 300BO
3) The tapered side case was viewed as less optimal for what they were trying to do?
4) Necking up the 223 case would make the Blackout seem a less radical step?

 

Its because it has cool name and uses the same bolt as 556 in an AR.

And people didn't used to understand how to get .39 to run well in an AR so it got a bad name in the past.

My 7.62x39 AR is my favorite rifle. Mostly because its so cheap to shoot and I like how the heavy bullets knock stuff around down range.

 

Its because it has cool name and uses the same bolt as 556 in an AR.

And people didn't used to understand how to get .39 to run well in an AR so it got a bad name in the past. .

No offence intended, but I have yet to have anyone I know who runs one hard.... Like something I would depend on with my life claim any success with it claim that the new AR 47's make the grade.

Plinking and a fun gun: sure.


OP:
There's a lot of fads.

The ability of the .300 to be loaded with 556 brass and .30 bullets is a big factor.

The ability to be chambered in a semi (AR) SUCCESSFULLY (reliability wise) as well as a manual is big.
I bought a Remington model 7 before I bought a .300 AR upper.

The fact is that every AR that's NOT an AR15 has.... Long term parts issues.

I remember an AR10 that took HK91 mags. Great idea.
Now 15+ years later.... Good luck getting parts.

The AR10 is GETTING there in "Standardization" but isn't there yet.

So, crappy AR options in x39, long term parts issues, desire for a semi (AK's don't suppress well.) Needing different mags vs using 556 etc

I'm .sure you know that everything but the .300 barrel works with 556 with Ar's

Etc.


Also, 10 years ago the subsonic 7.62x39 offerings were crappy killers.

I was actually planning on starting a thread about good "killing ammo" projectiles that were .311, and performed well at subsonic speeds.

I recently picked up a Ruger American in 7.62x39 to go with my Model 7 in .300 blk, and intend on doing some compare and contrast.

I REALLY LIKE it's ability to use mini 30 mags (paid $15 for a 20 rounder today)


If your JUST using a manual, and just for fun.... X39

If your playing like me or have lots of different guns.... Meh

But if you don't have 40+ different types of ammo, commonality is a good thing. (If I were to use an AR pistol it would be in .300 or 9mm, NOT 556.) I
I HAVE 556 pistols, but as toys.


If there some good subsonic projectiles for the x39 I can see the (my) .300 guns going unused or going away.

Otherwise:

Have you HEARD a suppressed .300?
Add that to the above.... And that's why


$0.02, YMMV.

 

Here are a couple of youtube videos comparing 5.56 and 300BO unsuppressed, 5.56 suppressed and 300BO suppressed (sub and supersonic).

As they discuss, video camera mics don't do it all justice, but the down range camera shots demonstrate the most realistic difference.

The effect (they only briefly mention) of suppressors in making it very hard to identify the direction rounds are coming from is quite real.

They even mention survivalism - but fair warning, they also say the "f word" a few times too.

 

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If I were to modify an upper to shoot 7.62x39, I not only need a new barrel, but a new bolt & mags & most of the AR style mags that feed 7.62x39 aren't usually as reliable as regular AR mags or AK mags. I can get an AR kind of looking rifle that shoots 7.62x39 that still needs a different barrel & bolt but will accept AK mags which also means I now need a special lower. I found that changing a barrel isn't that hard & swapping uppers while a bit more expensive is even easier still. I could still use the same entire BCG with the 300BLK so that would be one less BCG to buy if you are trying to save $. Also fewer varieties of spare parts to keep on hand with a 300BLK in an AR vs. a 7.62x39 in an AR, really just the barrel is the only spare you'd need that is different, so all the mags & other parts work fine. The minute bit of difference in ballistics isn't worth the hassle of dealing with all that other crap.

.

 

Just tell everyone you are shooting 7.62x35. Most of them won't think twice and ask you why aren't you shooting 7.62x39.

 

300BO is a good round. It's a 300ish yard round like x39, or arguably .556.
Supersonic bullets are GTG, but it really shines suppressed.

Did you know that sub 220gr's have been shown to defeat "bullet-proof" glass?

https://www.80-lower.com/blogs/80-lower-blog/300-blackout-vs-body-armor-and-bulletproof-glass/

They slay deer in the 0-100 yard range too. :thumb:
Sectional density is a thing, yo.

 

No offence intended, but I have yet to have anyone I know who runs one hard.... Like something I would depend on with my life claim any success with it claim that the new AR 47's make the grade.

No offense taken. I have not taken mine to war so I can't speak about how it would hold up under that use. I just know mine has been flawless so far for hunting and plinking.

The minute bit of difference in ballistics isn't worth the hassle of dealing with all that other crap.

Its not the ballistics, its the logistics, 7.62x39 is cheap and common, .300blk significantly less so.

If .300 blk was as cheap and common as 7.62x39 there would be no argument, .300blk would be the obvious choice.

 

Shooting an AK, SKS, Mini-30, or bolt action rifle, the greater case capacity gives the 7.62x39 the advantage. Especially if you are handloading that larger case with soft point expanding bullets, and using it for hunting.

Shooting a short barreled AR pistol, whats the point? Its just a stupid toy anyway.

 

........
Shooting a short barreled AR pistol, whats the point? Its just a stupid toy anyway.

The best gunfighters in the world disagree.

Virtually every SOF unit in the Western World (including Seals and Delta) have used 10.5" Barreled ARs as their primary CQB (Close Quarters Battle) gun for the last 15 years or so.

Most have been chambered in 5.56mm (often suppressed) and occasionally in 300BO.

M4s fitted with 10.5" uppers and Mark 18s fitted with Surefire cans are pretty ubiquitous in that world.

https://en.wikipedia.org/wiki/Close_Quarters_Battle_Receiver

Lot's of bad guys have been shot with those.....

Watch the last 30 minutes of the movie "Zero Dark Thirty" to see a realistic portrayal of those sorts of guns being used on the Bin Laden raid.

 

I can't...... Cause I feel the same way.

Sure, the 300BO is a fine round.

But the lovely 7.62 is well-performing load that is DIRT CHEAP!!!! $162 a 1000 was my last purchase. 300BO is going to cost you.

I am a HUGE FAN of a 7.62 Mutant AR..... When they are made with top-shelf components and steel mags... they are spectacular!!!!

I've even got a Howa bolt 7.62 that is an awesome gun.

........

 

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The price for brass cased ammo, which as a reloader is what I buy is almost the same for 300BLK vs 7.62x39. Not to mention if you look for factory subsonic loads in 7.62x39 vs 300blk, the x39 stuff is hard to find and as expensive if not more expensive than the 300BLK. If someone already has guns that shoot 7.62x39 & especially if shooting steel case cheap ammo is good enough for them, then that is probably a better option for them. If you don't own any AK's, SKS's or anything else in 7.62x39 but are looking at getting an upper for your AR to shoot 7.62x39, you'd probably be better off with the 300BLK. Uses the same bolt as well as mags which can be had for a lot less than the x39 mags that aren't as reliable. Also the AR bolts for the x39 are thinner & aren't as rugged as the 5.56 bolts. You can spend even more for an ARAK, mutant, or other versions of AR looking guns that take AK mags & shoot x39 ammo, but at that point, I'd rather just have an AK.

.

 

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The price for brass cased ammo, which as a reloader is what I buy is almost the same for 300BLK vs 7.62x39. Not to mention if you look for factory subsonic loads in 7.62x39 vs 300blk, the x39 stuff is hard to find and as expensive if not more expensive than the 300BLK. If someone already has guns that shoot 7.62x39 & especially if shooting steel case cheap ammo is good enough for them, then that is probably a better option for them. If you don't own any AK's, SKS's or anything else in 7.62x39 but are looking at getting an upper for your AR to shoot 7.62x39, you'd probably be better off with the 300BLK. Uses the same bolt as well as mags which can be had for a lot less than the x39 mags that aren't as reliable. Also the AR bolts for the AK are thinner & aren't as rugged as the 5.56 bolts. You can spend even more for an ARAK, mutant, or other versions of AR looking guns that take AK mags & shoot x39 ammo, but at that point, I'd rather just have an AK.

.

why would you reload for 7.62x39 anyway? fully loaded ammunition costs less than what you're going to buy .30 caliber unloaded bullets for, and the ammo isnt just inexpensive, but well suited to feed a rifle intended for fighting or defense.. you'll gain nothing from reloading 7.62x39

 

it exists because many AR-15 fanboys have been convinced 5.56 is inferior, and they need a 30 cal, but AKs are "commie" weapons that shoot 182 MOA, and oh god the recoil as you struggle to hit a barn!

as an actual weapon that will actually be used, yeah, 7.62x39 is better, and you can get good ammo for way cheaper, and is actually a proven caliber and will always be available, and plentiful

 

You must not reload, as this is super-stupid.
Sure, crap steel case ammunition is both cheap and cheap
Just using a single example, Barnes TSX


Caliber7.62x39
Weight123
S.D.0.183
B.C.0.275
Length0.985
Box QTY50
Catalog #30387

I can reload for a fraction of the cost from an ammunition manufacturer using the super good TSX
The difference really shines with premium bullets
Lot of nonsense as usual

As for the 300 BO
I have a few uppers
Love the sub-sonics
The 125 grain bullets do what needs to be done
Versatile round
You can hate on any round for good reason
Does it do the job as intended ?????
Yes it do
It is popular, and growing in popularity, and has a legit place
Don't like it, don't use it

I really do not hate on any particular ammunition
Get what you like and be happy

 

Supersonic there is very little difference ballistically. The 300 is easier to run in the AR platform. The 300 is easier to acquire over the counter quality hunting ammo. The 300 is easier to reload (brass and bullet selection) for hunting.

I’ve shot a lot of deer and hogs with both rounds. The 300 is better, not because of it’s ballistics, but because of bullet choices.

All the above being said, the 300 is really best suited in a SBR, shot subsonic and suppressed.

Hunting with 190ish gr subsonic expanding bullets is where it’s at. I haven’t shot any game over 120 yards with this setup. The sound the bullet makes when it hits the animal is akin to the sound of a fastball hitting wet newspaper or a padded backstop. The bullets pass through and the wound channels are very similar to a broad head.

 

Ever since I’ve ran my 300 with a 9” barrel I don’t think I can go back to a rifle. It’s just that much better imo.

 

I kinda want one because cheap ammo sounds like a great thing.

However, all those specialty parts, mags, and temperamental reliability doesn't really sound so cool, so no thanks...

 

Many opinions here...pro and con. As for me, neutering a 30 cal rifle cartridge to travel at subsonic velocities is a crime against nature. There are other ways to go subsonic. 9mm, 45, 22lr, etc.

 

I don't hate on any particular ammunition either. Agree with Swilling, get whatever you like and enjoy it.

My selection came down to logistics. The LBE I have all fit 5.56 magazines. So .300 uses the same magazines. Same with spare parts, as Chuckleberry noted. ARs are common all across the US, and if you need a part for your .300 you're likely to find another AR owner somewhere with that part.

After some catastrophic event, if you need to evac your current location there is a limit to what you'll be able to take with you. Logistics limitations suggest multiple weapons per person may not make the cut. Someone might pack out two uppers with one lower, though, rather than two complete rifles.

My SBRs are fine for the engagement distances I'm likely to encounter, as noted they're both (5.56 and .300) able to hit reliably out to 200 meters or more. I'm not hunting with them. Furthermore, if you're moving around in vehicles they're easier to use as truck guns than longer weapons.

It all comes down to personal circumstances. My buddy has an AR in 7.62x39, and he loves it. I've fired it, and its a slick rifle. He's just set up differently than I am. He's not really a survivalist, but does a lot of training with that rifle and it works for him.

My logistics outlook is just different from his. Use whatever meets your needs.

 

It's an attempt to use one bolt face to handle both .30 subsonic (main reason the .300 BLK exists) and the 5.56. Using this notion, it makes a certain kind of sense if the BLK is kept around for quietness' sake.

 

Why not just "down load" 223 / 5.56 rounds into the subsonic range rather than creating a 300 Blackout load?

 

That's why I really enjoy steel cased 5.56 ammo.

See, I've never had very good luck with steel cased 556 ammo. Part of they I went x39, as that caliber was designed for steel cases in the first place. Straight wall and steel case have just never mixed very well for me.

Completely false in terms of the 5.56, though true for the X39 round.

I've never had a failure to feed with my x39 AR. The CCPD x39 mags I have are actually some of nicest AR mags I have.

But like I keep saying, its all cost. When I can get .300blk for the cost of 7.62x39 I'll switch over and not look back.

 

See, I've never had very good luck with steel cased 556 ammo. Part of they I went x39, as that caliber was designed for steel cases in the first place. Straight wall and steel case have just never mixed very well for me.



I've never had a failure to feed with my x39 AR. The CCPD x39 mags I have are actually some of nicest AR mags I have.62.

But like I keep saying, its all cost. When I can get .300blk for the cost of 7.62x39 I'll switch over and not look back.

i would rather have 5.56 over either tbh

 

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I keep forgetting that 300blk can't be used for hunting.

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steel cased 5.56 costs about the same..

Yes, but as I say, its been a lot less reliable for me than steel cased x39.

Steel cases do not rebound as far after being fired as brass. Which is not a problem for a highly tapered case like x39, but can be for an AR.

The only problems I've had with AR's period has been with steel cased 556. I do not consider it a reliable ammunition type in that caliber.

 

the taper has little to do with it

 

Going to add; the tapered cartridge is A key, not THE key, to the reliability of the AK47 series of rifles.

So let's not get our panties in a bunch over semantics.

 

Yeah, I should have phrased it that way as well.

 

AK bolt handle serves the purpose just fine. Ditto the Garand bolt handle IIRC....

 

also, steel cased 5.56 is more problematic than steel cased 7.62, not because of some misplaced belief about taper, but simply because steel cased 5.56 ammo is largely garbage, several hundred feet per second slower than equivalent brass cased options which is significant enough to cause problems

 

https://www.pewpewtactical.com/brass-vs-steel-ammo/

 

I remember seeing that article posted in another thread here. Extraordinary that some people want to continue arguing for the sake of arguing. Maybe they should buy decent steel cased ammo instead of the super cheap crap.

For the record, I do NOT shoot steel cased ammo especially in the NMARs. And, a teammate of mine has 1st hand experience what it is like to shoot lacquer coated steel cased ammo in rapid fire strings out of a........NMAR. Not a good idea.