300 Blackout or 7.62X39?

[rg1911]

A search did not find this question. If I missed it, please just point me towards the thread.

Once again I have an AR15 lower and no upper. Since I don't need a fourth AR in .223, I thought I'd try either the 300 Blackout or 7.62X39. Bear Creek Arsenal has some pretty good prices for complete uppers, including the bolt carrier group.

It appears that both cartridges will require their specific magazines, and the 7.62X39 would also require a different bolt carrier group.

My current understanding is that the 7.62X39 would offer a bit more power from a 10" (or so) barrel; plus I already reload for it.

The .300 Blackout, (for which I do not currently reload) has a large following, and I assume there is a reason for that.

Is one a relatively clear choice compared to the other?

Thank you,
Richard

 

[vinniedelpino]

A search did not find this question. If I missed it, please just point me towards the thread.

Once again I have an AR15 lower and no upper. Since I don't need a fourth AR in .223, I thought I'd try either the 300 Blackout or 7.62X39. Bear Creek Arsenal has some pretty good prices for complete uppers, including the bolt carrier group.

It appears that both cartridges will require their specific magazines, and the 7.62X39 would also require a different bolt carrier group.

My current understanding is that the 7.62X39 would offer a bit more power from a 10" (or so) barrel; plus I already reload for it.

The .300 Blackout, (for which I do not currently reload) has a large following, and I assume there is a reason for that.

Is one a relatively clear choice compared to the other?

Thank you,
Richard

In an AR? 300bo hands down. Less tinkering to get it to run well and a much better bullet selection. .308s will work in a 7.62x39 but accuracy may suffer.

plus you don’t need a new bcg or mags that can only be loaded short a few rounds to feed reliably. Load data is also readily available for the BO where 7.62 is lacking.

I use cut down and resized lake city with flawless results in the 300BO too.

I never understood the appeal of a 7.62 AR other than the availability of cheap Russian ammo. I wouldn’t hold my breath on that coming around right now.

 

[fdkay]

You don't need special mags for the .300, though some work better than others.
The AR is not designed for the AK mags, you would need the specialty mags, which are available.
The .300 is designed for 10 inch barrels, the 7.62x39 is designed for 16" barrels.
What bore diameter are you going to get for the x39?
If the standard .311, you are very limited on bullet selection.
If .308, you shouldn't be firing bulk ammo in it, as it will drive up pressures.

The BO has a better selection of bullets, however, they have very few that are specifically designed for the BO, I believe that barnes makes two, they are excellent, but pricey.
In a pinch, BO brass can be made from 5.56 brass.

 

[rg1911]

Very good points favoring the 300 BO, and Bear Creek has a 7.5" complete upper on sale for $226.

Thank you,
Richard

 

[db2000]

I have a Bear Creek. It functions just fine with mil spec lowers. I use Midways “AR Stoner” brand 7.62 x 39 mags and haven’t had any issues. It shot 1.25” groups at 50 yards with 123 gr Russian White Box ammo.
That being said, if you’re choosing and you don’t have a stock pile of 7.62 x 39 ammo then 300 BO. It’s much more accurate and I load super and sub sonic.

 

[drewthebrave]

I have zero faith in BCA... I'd rather buy from PSA or Anderson if I was pinching pennies.

I think .300 BLK is the better choice for an AR platform on a budget. Though the .300 HAM'R seems more suited to my tastes.

 

[roostercogburn98]

My 7.62x39 took some tinkering and was picky on mags it liked. Once I figured that out it runs like a champion. It is a 7.5 inch barrel. I also have. 10.5in 300 BO, both are equally fun, but the x39 wins for the loud factor. If quiet is your game, a shorty x39 won’t get you there as where a short BO still could.

 

[rg1911]

I have zero faith in BCA... I'd rather buy from PSA or Anderson if I was pinching pennies.

I think .300 BLK is the better choice for an AR platform on a budget. Though the .300 HAM'R seems more suited to my tastes.

What was the bad experience you had with BCA?

Thank you,
Richard

 

[Lo-Profile]

Another vote for 300bo.
I have 2, a 8" and a 16" .... Both shoot extremely well. Both are DI gassed, the 8" can be suppressed.
Unless your going to handload longer / heavier bullets you won't need different magazines for 300bo. Even then USGI mags work great.
I use FDE magazines for 300bo and black for 5.56 .... Helps with knowing what's in the magazine. I also rattle can the guns FDE for the 300's since all mine are fairly close in how they're setup. Don't want any mistakes with what gun is what at the range. Especially if you have both 300 & 5.56 or other AR's in other calibers

 

[Snuby642]

Well one is the choice of communists around the world.

The other is home grown.

 

[RUTGERS95]

x39

 

[towerofpower93]

I love my 7.5" x39 upper, but 300BO really is the superior cartridge when it comes to ease of reloading and finding mags that work for it.

If you were just wanting a noise maker, and Russian ammo wasn't going to be getting turned off, I'd say x39. But a new set of dies doesn't cost much and you'll find the 300BO easy to load for in no time. Plus, if you have a can, the BO is an easier round to load subs for.

 

[Sleddog30]

I have a Windham in 7.62x39 and a built one also. I used a Bear Creek complete upper for the build. They both shoot flawlessly. No issue with mags. I use C products defense, now Duramag, with no issues. I also have one from another manufacture, can remember the name at the moment, but that one runs with no issues also

On the ammo side, I have well over 3000 round from various manufactures. Both brass and steel case. I stopped using Red Army because the primers where getting pushed into the pocket on 25% of them causing failures to fire. But they worked on second strike.

I primarily run steel case in both. The Bear Creek is a great truck gun. The Windham is a tack driver at 100. Hollow points in either does a great job on hogs and other varmints.

 

[Clayman]

On an AR 300 blk without question. supers/subs, compatibility, etc

If you want x39 buy an AK.

 

[DukeGSP]

a .300blk with a > 10" barrel is hot garbage. if you're wanting to shoot subs, then of course. but .300 blk with subs won't ethically kill anything. 300 blk ammo is still stupidly priced while 7.62 is roughly a 10 dollar bill even in these current times. i own both. we shoot pigs A LOT and the .300 blk even with supers would be my last choice.

 

[Clayman]

a .300blk with a > 10" barrel is hot garbage. if you're wanting to shoot subs, then of course. but .300 blk with subs won't ethically kill anything. 300 blk ammo is still stupidly priced while 7.62 is roughly a 10 dollar bill even in these current times. i own both. we shoot pigs A LOT and the .300 blk even with supers would be my last choice.

Discreet ballistics selous subs will absolutely ethically kill hogs, deer, etc.

110 tac tx kills hogs without issue.

 

[sparky702]

I own 4 300 blackouts and have killed deer and pigs with every one of them with both sub's and super sonic .300 blackout would be my last choice hunting antelope out on the great plain's but it works great out here in the ozark foothill's .

 

[drewthebrave]

What was the bad experience you had with BCA?

Thank you,
Richard

I tried one of their side charging uppers and the barrel extension fit in the upper receiver like a hotdog flopping around in a hallway. I heard mixed reviews on their quality but decided to give them a shot anyway. After wasting time, money, and effort troubleshooting issues with cheap parts in the past, I simply don't care to play the "quality" lottery anymore. I'll gladly spend a bit more to get quality parts from reputable manufacturers and spend a lot less time troubleshooting problems at the range these days.

 

[Yondering]

a .300blk with a > 10" barrel is hot garbage. if you're wanting to shoot subs, then of course. but .300 blk with subs won't ethically kill anything. 300 blk ammo is still stupidly priced while 7.62 is roughly a 10 dollar bill even in these current times. i own both. we shoot pigs A LOT and the .300 blk even with supers would be my last choice.

Owning something doesn't mean you know what you're talking about. Plenty of proof in that when you talk to people claiming the 300 doesn't kill well, and then it turns out they're shooting 147gr FMJ ammo or some other stupid choice like that.

Bullet choice matters a whole lot more than the cartridge, and the 300 has some far better bullet options than the x39. The difference in velocity between the two cartridges isn't enough to make a lick of difference. So, if you really think the x39 kills that much better, it's probably a result of your bullet choices or your shot placement.


As to the OP: dude, this is probably one of the single most debated questions in gun forums for the past 10 years. You really couldn't find any info about it?

 

[DukeGSP]

Owning something doesn't mean you know what you're talking about. Plenty of proof in that when you talk to people claiming the 300 doesn't kill well, and then it turns out they're shooting 147gr FMJ ammo or some other stupid choice like that.

Bullet choice matters a whole lot more than the cartridge, and the 300 has some far better bullet options than the x39. The difference in velocity between the two cartridges isn't enough to make a lick of difference. So, if you really think the x39 kills that much better, it's probably a result of your bullet choices or your shot placement.


As to the OP: dude, this is probably one of the single most debated questions in gun forums for the past 10 years. You really couldn't find any info about it?

so because my opinion doesn't jive with yours, i automatically have no clue what i'm talking about lol.... got it.


i've shot everything from a 110 to a 220 out of my .300 blk and as i stated it just doesn't kill very well. the X39 isn't the best either. he asked what was better of the TWO and i gave my opinion. i would just build a 6.8 and delete this thread.

 

[MadDuner]

300 BO and 7.62x39 both make the same size hole.
They both run reliably in the AR platform.
I run both.

Go price or find ammo....
If you want plentiful factory ammo and at a greatly reduced price vs the other then the x39 is the right choice.

If you are going to be loading your own stuff 100% of the time than go 300.

Or get both and see for yourself.

 

[fdkay]

a .300blk with a > 10" barrel is hot garbage. if you're wanting to shoot subs, then of course. but .300 blk with subs won't ethically kill anything. 300 blk ammo is still stupidly priced while 7.62 is roughly a 10 dollar bill even in these current times. i own both. we shoot pigs A LOT and the .300 blk even with supers would be my last choice.

Do you know how much difference there is between a sub-sonic 220 SMK from .300 Blk and a sub-sonic 220 SMK from a .308 Winchester, or a sub-sonic load from a 7.62x39?


None.
I'm not sure what compelled you to include that bit of info, as inaccurate as it is.

As far as supersonic, yes the x39 starts faster, but the extremely short, stubby bullet of the mil-spec ammo, it loses steam rather quickly. Not a big deal for realistic engagement ranges.
The barnes 110 grain bullet specifically designed for the .300 has a vastly superior BC and sectional density. It may start a bit slower, but it hold its speed better.

If you want cheap ammo (for the time being), 7.62x39 is the answer, it is a very well designed cartridge, it is not superior to the BO and neither is the BO superior to the x39, they both fill their niche.
The biggest advantage of the BO is you can run supers and subs and not worry about an adjustable gas block.

 

[DukeGSP]

Do you know how much difference there is between a sub-sonic 220 SMK from .300 Blk and a sub-sonic 220 SMK from a .308 Winchester, or a sub-sonic load from a 7.62x39?


None.
I'm not sure what compelled you to include that bit of info, as inaccurate as it is.

As far as supersonic, yes the x39 starts faster, but the extremely short, stubby bullet of the mil-spec ammo, it loses steam rather quickly. Not a big deal for realistic engagement ranges.
The barnes 110 grain bullet specifically designed for the .300 has a vastly superior BC and sectional density. It may start a bit slower, but it hold its speed better.

If you want cheap ammo (for the time being), 7.62x39 is the answer, it is a very well designed cartridge, it is not superior to the BO and neither is the BO superior to the x39, they both fill their niche.
The biggest advantage of the BO is you can run supers and subs and not worry about an adjustable gas block.

the only reason i mentioned the .300blk for subs is because it's arguably one of the quietest, more quiet than my x39 suppressed IMO. other than you misunderstanding the point i was originally making, it sounds like you're pushing the x39. calm your tits buckwheat.

 

[fdkay]

the only reason i mentioned the .300blk for subs is because it's arguably one of the quietest, more quiet than my x39 suppressed IMO. other than you misunderstanding the point i was originally making, it sounds like you're pushing the x39. calm your tits buckwheat.

You have a comprehension issue

 

[MadDuner]

Get both and see.
It’s not like you will suffer any depreciation over time.

 

[david walter]

The answer is 300 HAMR.

 

[bunsen27]

The answer is 300 HAMR.

That was the answer I came up with too! I did already have a .300BLK though.

 

[DukeGSP]

You have a comprehension issue

whatever you say guy.

 

[david walter]

The HAMR and BO are more dissimilar than similar.

The HAMR is a hunting round, designed from the start for deer and hogs, and to duplicate the ballistics of a 30-30 in an AR. That's a 1 in 15" twist designed for 110 - 150 grain bullets, with a noticeable sweet spot at 125-135.

The BO was designed as a 44 special in an AR, so heavy bullets. Later people discovered light bullets, but those cap out at 110 or so and reappear at 210 or 220, completely skipping the majority of good 30 caliber hunting bullets.

That was the answer I came up with too! I did already have a .300BLK though.

 

[roostercogburn98]

The HAMR and BO are more dissimilar than similar.

The HAMR is a hunting round, designed from the start for deer and hogs, and to duplicate the ballistics of a 30-30 in an AR. That's a 1 in 15" twist designed for 110 - 150 grain bullets, with a noticeable sweet spot at 125-135.

The BO was designed as a 44 special in an AR, so heavy bullets. Later people discovered light bullets, but those cap out at 110 or so and reappear at 210 or 220, completely skipping the majority of good 30 caliber hunting bullets.

What’s your take on a 150g spire point in the blackout? I’ve had pretty good accuracy for a 10.5 in barrel. I loaded some to deer hunt with but never did. I just use the 44 mag handi rifle more I guess.

 

[Yondering]

What’s your take on a 150g spire point in the blackout? I’ve had pretty good accuracy for a 10.5 in barrel. I loaded some to deer hunt with but never did. I just use the 44 mag handi rifle more I guess.

Garbage in that application. They’re too slow to perform.
You have to consider velocity from the rifle compared to minimum expansion velocity. If that comparison is very close or upside down, like this case, don’t hunt with it.

 

[roostercogburn98]

Just curious cause what the opinion here was. Some say it will expand starting at 1700, but maybe not efficiently. If I remember, the magic FPS number starts around 2100 for that bullet but I could be wrong.

 

[Yondering]

TheThe BO was designed as a 44 special in an AR, so heavy bullets. Later people discovered light bullets, but those cap out at 110 or so and reappear at 210 or 220, completely skipping the majority of good 30 caliber hunting bullets.

Hmm.
The sweet spot for hunting bullets in the 300 is 110-125gr, same as the Hamr. The 125 NBT is one of the very best available in my experience.

Also I don’t think your info is quite straight on the heavy stuff. In an AR, the 300 Blackout was intended for dual purpose from the start. It did come from the heavy subsonic 300 Whisper and 300/221 rounds, but those weren’t designed for ARs necessarily.
Regardless though, what someone thinks it was designed for is a lot less important than what it can do.

 

[Yondering]

Just curious cause what the opinion here was. Some say it will expand starting at 1700, but maybe not efficiently. If I remember, the magic FPS number starts around 2100 for that bullet but I could be wrong.

The 2000-2200 range is common for most lead pointed cup and core bullets like that. Even in a 16” 300 you’ll have trouble pushing them that fast.

This is a good example where heavier is not better. The same design in a 125gr would be great.

 

[maddazzshooter]

A search did not find this question. If I missed it, please just point me towards the thread.

Once again I have an AR15 lower and no upper. Since I don't need a fourth AR in .223, I thought I'd try either the 300 Blackout or 7.62X39. Bear Creek Arsenal has some pretty good prices for complete uppers, including the bolt carrier group.

It appears that both cartridges will require their specific magazines, and the 7.62X39 would also require a different bolt carrier group.

My current understanding is that the 7.62X39 would offer a bit more power from a 10" (or so) barrel; plus I already reload for it.

The .300 Blackout, (for which I do not currently reload) has a large following, and I assume there is a reason for that.

Is one a relatively clear choice compared to the other?

Thank you,
Richard

The 300Blackout is a reloaders dream because of the abundance of 5.56/223 cases polluting the planet. There’s a vast amount available product combinations that one can use to make Ammo!! From the most high tech Lehigh Defense projectiles to the homegrown garage made cast lead ,if you are resourceful enough to always have Ammo!!! From dedicated Blackout powder to pistol and shotgun powder there’s something out there to make Blackout Ammo……..That’s my two nickels…. 5.56 mags work fine but Magpul mag800s work better…

 

[maddazzshooter]

Garbage in that application. They’re too slow to perform.
You have to consider velocity from the rifle compared to minimum expansion velocity. If that comparison is very close or upside down, like this case, don’t hunt with it.

Speer makes a 150gr Gold Dot especially for the 300blk that gets it done. They are designed to give you the highest velocity for a 150gr Blackout. Check out Speer’s load data!

 

[maddazzshooter]

Do you know how much difference there is between a sub-sonic 220 SMK from .300 Blk and a sub-sonic 220 SMK from a .308 Winchester, or a sub-sonic load from a 7.62x39?


None.
I'm not sure what compelled you to include that bit of info, as inaccurate as it is.

As far as supersonic, yes the x39 starts faster, but the extremely short, stubby bullet of the mil-spec ammo, it loses steam rather quickly. Not a big deal for realistic engagement ranges.
The barnes 110 grain bullet specifically designed for the .300 has a vastly superior BC and sectional density. It may start a bit slower, but it hold its speed better.

If you want cheap ammo (for the time being), 7.62x39 is the answer, it is a very well designed cartridge, it is not superior to the BO and neither is the BO superior to the x39, they both fill their niche.
The biggest advantage of the BO is you can run supers and subs and not worry about an adjustable gas block.

I believe that the obvious is overlooked . The 7.62x39 will never outperform the BO in the AR25 platform but it was never designed to. The 7.62 x39 was my reason to walk away from the 5.56 and not look back. The 300blk was my draw away from the 7.62x39.The ability to change the capabilities of your weapon by changing magazines cannot be taken lightly. Versatility!!! The blackout has it in spades!!!! It has only one cartridge that compares that I’m aware of…338 Spectre and then Blackout falls short everywhere but availability …… IMO!!

 

[erik72]

I have a 16" 300BO and a 16" 7.62x39. I reload for both and I currently find myself shooting the x39 more because I'm damn near out of small rifle primers and I'm not gonna pay "gouging" prices....yet. I have thousands of large rifle primers. I had parts available so all I had to buy was a barrel, bolt, and magazines. I recommend the C-products Duramags. I have not had one failure to feed or eject.

 

[MadDuner]

The C-products Mags are what I run also.
Zero 7.62x39 or 5.45x39 issues with any of my x39 ARs.

 

[r.tenorio671]

FWIW, take into consideration your locale and how that affects the availability now, and in the future, of a resupply of ammo or components if you reload, and those consumable parts that will need replacement. It appears the OP is looking at a "complete upper" caliber change so he/she would only need mags for a x39 conversion if the "complete upper" includes the BCG.

A 300BLK conversion would only require an ammo change as 300BLK works with any current 556 mag (and was designed to do so from the get-go).

 

[MadDuner]

Swapping different calibers and using the same mags brings ammo identification challenges if used in a SHTF situation or with more than a single person involved in the “feeding” of said weapon. If only the OP will ever be using it, then no problem.

I use color coding to keep calibers and similar looking mags from going into the wrong chamber - especially when I would take my kids or relatives shooting.

It’s still not foolproof, but I think it’s helped so far.

 

[4thandbleek]

I'd say .300 Blackout by a bit. 7.62x39 has issues running in ARs, but easier to obtain. you also have to consider availability of mags and parts.

 

[Velocity Chad]

300blk with supers is pretty damn close to a 30-30 that has killed as many deer as any round. My kid uses a 300blk pistol for deer hunting and has not had a deer take more than a step or two out of a half dozen. The Barnes black tips are money on deer out to 125yds from my experience.