Why 300 blackout instead of 7.62x39?

[Skarekrow88]

so what's the point?

Subsonic 300BLK for suppressing. Aside from that 300BLK offers nothing significant that 7.62x39 doesn't other than the ability to more easily have 7.62x39-like ballistics out of an AR platform without having it actually chambered in 7.62x39

Am I missing something...

You're not.

 

[stagpanther]

It's like that tomato juice commercial--once you've tried it you'll be smacking yourself in the head saying "Gee, I could have had a 300 Blackout!" LOL

The "technical headache coefficient" of the 300 BO is one of the lowest I've experienced on any AR derived platform outside of 5.56 itself.

All the rest is just "mine's better than yours" -CENSORED--CENSORED--CENSORED--CENSORED--CENSORED--CENSORED--CENSORED- match. : )

 

[Bartholomew Roberts]

But the idea that an AR in 300 AAC is "just a swap from one type of ammo to the other" is not so, or if it is I have never seen it. If anyone out there knows of some carbines that will allow this I wouyld LOVE to talk to the makers and find out how they are doing it. But as I said, in the last 6 years or so since I have been making them, I have yet to see a gun that you can do this with.

Talk to Remington then. They may not be able to build a 700 or shotgun worth a crap these days; but my factory AAC MPW 9" in .300 runs subsonic or supersonic, surpressed or unsurpressed just fine. No tweaking. No parts changes. It functions with pretty much all .300 ammo that will fit in the magazine so far.

As for what .300 offers, from the 9" barrel a 125gr is getting around 2050fps with no muzzle flash and less racket. A 123gr from a 16" AK is what? About 2350fps (depending on whose ammo)? So I'm getting about 87% of the velocity with about 56% of the barrel? Give or take. I'm also not going to be breaking bolts like a 7.62x39 AR will.

 

[Sharkbite]

I have made quite a few 300 Whispers on ARs and I have never made one or seen one that you could change the mag from loads at subsonic velocities to loads with supersonic ammo and have the rifle work.

Ive got Three 300blk AR's.
1. 9" AAC SBR
2. 10.5" homebuilt pistol
3. 16" barrel swap on a Bushy gun (pistol gassed)

All 3 work in all 4 modes.

Simply swap mags subs to supers and back again. Add the can if you want. 100% function and BHO

I dont down load my 30rnd mags. Stuff em full and go. In fact i have mixed subs and supers in a mag thru my AAC SBR and the gun just ran till empty.

 

[FrankenMauser]

Why is .300 Blackout better?
I don't think it is. It's just my opinion, but I think .300 Blackout is just a glorified .30 Carbine that managed to get a serious head of steam behind the marketing train, and the manufacturers are going to push that 4-8-8-4 at full speed until it derails...

The AR design works poorly with cases that have too fat a rim or too much taper. The 5.56 case has a .378 rim, the SPC case has a .422 rim, and 7.62x39 has a .447 rim. It turns out that's a bit too much and causes problems both with the bolt assembly and with the magazine/feed system.

Hmm....

You may want to check in with some .458 SOCOM (or even .375 SOCOM) owners and/or manufacturers before you publish that opinion for peer review. The case head is comparatively massive at 0.473" nominal. And the case body is larger than 0.540". Yet it feeds just fine from standard magazines.


As for taper... It's not a problem with the upper. It's a problem with the geometry of the lower requiring several inches of the magazine to be dead-straight.

 

[mavracer]

You may want to check in with some .458 SOCOM ......... Yet it feeds just fine from standard magazines.

Haven't seen many 30 round 458 Socom mags

 

[SR420]

I looked at the 300BLK and decided to stay with my reliable x39 AKM.

EDIT: My AKM suppresses well & I can run Subs with just a mag change.

 

[Llama Bob]

You may want to check in with some .458 SOCOM (or even .375 SOCOM) owners

.458 SOCOM has been known to have bolt problems. The feed problems are mitigated by going single stack, but of course at the loss of large amounts of capacity.

Put it this way: I would certainly never trust an AR-15 chambered for anything with a bigger bolt face than a SPC case. That case is big enough to put plenty of powder behind any reasonable diameter bullet anyways.

 

[Sharkbite]

I looked at the 300BLK and decided to stay with my reliable x39 AKM.

Its not a question of AR vs AK. Its a question of 300blk functionality.

My 9" SBR in 300blk give me the
Size of an MP5
Ergo's of an AR
Power of the x39
Ability to run Subs with just a mag change
Suppresses well

All with just a barrel swap. No special parts or mags.

It just offeres so much that the x39 guns dont.

 

[FrankenMauser]

Haven't seen many 30 round 458 Socom mags

Read the post.
Then read it again.

No mention was made about 30 round mags, in my reply or the original post that I quoted.

And, try some common sense.

.458 SOCOM has been known to have bolt problems. The feed problems are mitigated by going single stack, but of course at the loss of large amounts of capacity.

I believe you're thinking of the things that two well-known companies that love proprietary parts and cartridges make or used to make, that they call ".458 SOCOM", but the uppers are really just knock-offs that spend most of their lives in the hands of UPS, going back and forth for factory repair. (The only major company making the real thing, Rock River, suffered a string of broken bolts, but it was a metallurgy issue - not a geometry issue.)


It's already single-stack, even in GI mags with 5.56 followers. How do you convert single-stack to single-stack? (Yes, I know about flat-top followers, but they don't change magazine body geometry.)
Guys that have magazine problems nearly always fall into one of four categories:
1. They're running P-Mags against the advice of every .458 SOCOM manufacturer, other owners that have tried it, and even Magpul.
2. They stuffed something ridiculous into the cartridge, like a 480 gr Woodleigh Hydrostatically Stabilized solid, and tried to modify the magazine to make it feed. But, now the magazine won't feed anything.
3. They're using beat-to-crap magazines that should have been recycled 10 years ago, and don't work with anything else, either.
4. They were getting scratches on their brass, so they tweaked and filed the feed lips. Now, it won't feed worth a crap.

Notice a trend? They're the same problems encountered with any other cartridge in an AR: People screwing stuff up, being cheapskates, or running the wrong parts (6.8 SPC in a 5.56 mag?); and not taking responsibility for their own actions.
"Just blame the parts, instead."


And I think I'm done with .458 SOCOM in this thread. I don't want to be the guy that gets it locked for derailing the discussion.

 

[Wyosmith]

Well perhaps I am wrong here, but I REALLY would like to see a 300 on an AR that can work with both Supersonic and subsnonc. I have been unable to get them to work without parts changes.
I would LOVE to see one up close and see what kinds of Mods are being used to do this.

 

[Bartholomew Roberts]

It's just my opinion, but I think .300 Blackout is just a glorified .30 Carbine

A 110gr projectile out of a 9" .300 BLK barrel is travelling 200fps faster and has half the drop of a modernized 110gr .30 carbine from a 16" barrel.

 

[Llama Bob]

Well perhaps I am wrong here, but I REALLY would like to see a 300 on an AR that can work with both Supersonic and subsnonc. I have been unable to get them to work without parts changes.
I would LOVE to see one up close and see what kinds of Mods are being used to do this.

Wouldn't it just be an adjustable gas block at most?

 

[A pause for the COZ]

It's just my opinion, but I think .300 Blackout is just a glorified .30 Carbine

I get that, When I first got one. My main use was as a replacement 30 carbine.
But to say 300 Blackout is just a glorified .30 Carbine Is missing the point.

The 300 Black out can do every thing you can do with a 30 carbine. Plus much more.
The 300 Black out can do everything you can do with a 7.62x39 plus every thing less.

So basically instead of one package that's good at one thing. You can go from the 30 carbine and end at the 7.62x39 and every thing in between. And thats just as a carbine.
Once you get into SUBs in a SBR you've now opened a whole new path.
its by far with out a peer in that regard. Sure you can find one format that will perform one specific job better. But it wont be acceptable in any of the others.

I mean we get into this every time it comes up. The 6.8 spc guys say. " The 300 BLK cant do what I can do". Sure but you cant even do 20% of what I can do. and I can do it cheaper. I know a couple of spc guys who maybe have 250 rounds through their guns.
Whats the point in that? I have over 25,000 rounds through my 300 blk. Because I can afford to shoot it for a little more than 22lr money.

Its one of those guns though. Similar to the 327 magnum. Guys ether love it to death or they hate it. Not much middle ground to be found.
good thing we are not limited to one gun. We get to buy what we like.

 

[rickyrick]

I don't own one, so my opinion may be of little use.

I've seriously considered building a .300bo carbine, very seriously. I originally rebuffed it as another boutique cartridge.

The reason is this, you can get a somewhat "useable" 30 caliber cartridge in an AR with off-the-shelf components. Heck, you could even possibly "try it out" on an existing AR for 80-100 bucks. In shooting terms, that's a small investment.

It will most likely be my next project as I now have the .223 range covered with everything from 10.5" to 24".

 

[A pause for the COZ]

For me and it might just be me. because they sell a zillion of them.
I gave up on any 5.56 shorter than 20 inches.
I have a 1-9 carbine upper just sitting collecting dust.
Sure I could go blasting with it. Makes allot of noise and pokes holes in paper.
It was not until I went back to its roots and found out what Mr Stoner had in mind when he came up with it in the 1st place.
1-12 20 inch rifle that I fell in love again. IMOP every thing else they have done has been to try to get the 223 to do some thing its not good at.
It good at pushing a light bullet (55gr) really really fast and putting them in almost the same hole at 100 yards.
But I digress and apologize for straying a bit off topic. But I love my rifle.

 

[iraiam]

For me the choice of 300 Blackout was because I can use all the same magazines/lowers and have a .30 caliber AR. I only have 1 300 blackout that is set up for full power rounds, I'm happy with it, but don't shoot it a whole lot.

 

[Sharkbite]

Quote:
Well perhaps I am wrong here, but I REALLY would like to see a 300 on an AR that can work with both Supersonic and subsnonc. I have been unable to get them to work without parts changes.
I would LOVE to see one up close and see what kinds of Mods are being used to do this.


Wouldn't it just be an adjustable gas block at most?

None of my guns has an adj gas block. All run subs to supers with ZERO change to the gun. Just switch ammo and go to it.

Its NOT some big industry secret. Lots of off the rack guns will do this. The problem i see is guys building guns and trying to build it like its a 556 gun. Different pressure curves and gas volumes means different port sizes and locations.

Most guys run into problems because they try to use a carbine length gas system on their 16" Blackout. Might be ok for a 556 but can be a problem for a 300BO. Use a pistol length gas system and a magnum pistol powder (H110/supers, 1680/subs) and it will run like a Swiss watch.

 

[gojuice101]

My main reason for going for the 300BLK was because I wanted an AR platform rifle for hunting, and regulations say .23 cal or larger. I wanted to be able to use everything I already had for the 223 guns (BCG and mags) so that pretty much ruled out everything else.

I also have a couple x39 guns. I don't really prefer one over the other. For me, they both have their purposes and they serve them.

 

[Theohazard]

Well perhaps I am wrong here, but I REALLY would like to see a 300 on an AR that can work with both Supersonic and subsnonc. I have been unable to get them to work without parts changes.
I would LOVE to see one up close and see what kinds of Mods are being used to do this.

Just like Sharkbite said, you don't need any special mods, you don't even need an adjustable gas block. Most of the 300 Blackouts I've seen didn't have adjustable gas blocks and ran supersonic ammo suppressed and unsuppressed, and subsonic ammo suppressed. And often they even worked unsuppressed with subsonic ammo too.

ACC sells 9", 12", and 16" 300 Blackout uppers, and they're all designed to run supersonic and subsonic with no parts changes and no adjustable gas block. My coworker's 9" AAC MPW pistol ran all 4 modes with no parts swaps and no adjustable gas block, and from the other responses in this thread it looks like that's pretty common.