8.6 Blackout 1:3 twist cast boolits are possible!!!

[HillbillyNC]

Not looking to start a discussion on the merits of the cartridge. This is an exciting time, being at the beginning of something that challenges traditional wisdom. A very few folks have begun to work with cast in the 1:3 twist barrel. There is a very detailed work up on one of the 8.6 Facebook groups that shows the cast boolits holding together until 1115fps with a 24bhn alloy but the poster declined to share the alloy ingredients/percentages. The mold used was a 338 dia 270 grain NOE spire point with no lube grooves. I would like to also do some cast experiments but wanted to get a heavier, flat point mold to work with. NOE has already manufactured, but is currently out of stock, the HTC339-315-FN-BZ1 315gr flat point. There is currently a post on the NOE forums directed at getting NOE to make more of these. Apparently the mold was originally designed for the 338 Specter but will also work in all 338 cal applications.

If you are interested in a 338 mold, and this would work for you in your pursuits, could you please sign up on the NOE forums page?

HTC339-315-FN-BZ1 (https://noebulletmolds.com/smf/index.php?topic=3412.0)

[waksupi]

At 1 in 3 twist rate, that isn't a rifled barrel, it's threaded!

[Larry Gibson]

At 1 in 3 twist rate, that isn't a rifled barrel, it's threaded!

No kidding........

[725]

Oh, my. That bullet must be hard and slow to survive a 1/3 twist.

[HillbillyNC]

At 1050fps, that's a mere 252000rpm.... But it's being done with success. I myself am looking forward to playing around with this and trying to leverage all the old wisdom and tricks to get it to work. Instead of hardening up the alloy to point of brittleness, my 1st experiment will be with copper infused alloys in order to lower the bhn and maintain bullet integrity. Ideally it would be awesome to have a subsonic 315gr flat point with the 1:3 twist that expands. The fast twist should go a long way toward expansion if you can strike the balance.

[dondiego]

What is there to gain from this twist?

[Dusty Bannister]

Pistol velocities from a rifle? Maybe it is just to see if it will work and how fast can it go with present technology and practices.

[Hanzy4200]

That caliber really interested me when I first saw it. I know I will need to be patient, and wait for more main stream manufacturers to offer rifles chambered in it. I know very little about it. Is there a parent case that in can be formed from?

[Hanzy4200]

Pistol velocities from a rifle? Maybe it is just to see if it will work and how fast can it go with present technology and practices.

It's designed to be shot suppressed. Like a larger .300 Blackout.

[technojock]

Wouldn't a .38 Special or 9mm carbine make more sense? They already shoot a boolit around 125g at subsonic speeds.

Tony

[kenton]

Wouldn't a .38 Special or 9mm carbine make more sense? They already shoot a boolit around 125g at subsonic speeds.

Tony

It would if you wanted 125gr boolits instead of 315gr.

I think the 8.6 blackout is an interesting idea. Not my cup of tea but I hope to hear more about what others are doing with it.

[stubshaft]

Personally, I think it is a waste of time and money, but to each their own.

[ebb]

I totally agree stub shaft. JD jones has been shooting 338 subs for years and never saw the need for the extremes that this cartridge is coming up with. I don't see how this survives for 2 more years. How much drop does this thing have at 200 with a 100yd zero. We are spoiled with the high-performance cartridges we have today and this is so low performance I don't see why anyone would bother. One of the guys that posts on bench rest central developed a sus sonic 50 caliber, with a super long sleek bullet and it was great only he couldn't stand the recoil for more than a shot or two.

[technojock]

Doesn't the .45 Colt shoot about a 300g bullet at subsonic velocity?

Tony

[475AR]

While I am not planning to jump on the 8.6 Blackout bandwagon, I think using cast bullets in that fast of a twist will cause accuracy issues with cast bullets, but it needs to be tested to be sure.
I have heard that using standard jacketed/ lead core bullets is cautioned against because they could blow up in flight, if that is true I don't think lead only bullets will be much better??

[Castaway]

Another designer cartridge and the only apparent advantage is to sell rifles. If you get one, you may find a spot for it in your safe next to your 45 GAP pistol

[Barry54]

What is there to gain from this twist?

They talk up the ridiculous twist being more effective on game. I would try one with a twist rate optimized for the 300 grain matching subsonic.

Are there any gel comparisons between subsonic with the 1:3 vs what JDJ used?

[475AR]

Another designer cartridge and the only apparent advantage is to sell rifles. If you get one, you may find a spot for it in your safe next to your 45 GAP pistol

Why everyone b hating on the GAP...:shock:
I built a 10" DI AR15, throated it to run 250gr bullets @ 850-950fps and it shoots beautifully and to top it off it is the quietest 45 caliber I have suppressed.:bigsmyl2:
It is so surprising I have KKM building me a 7" 45 GAP threaded barrel for my long slide G21, hopefully it will be as quiet as MY GAP AR15.

[reddog81]

Doesn't the .45 Colt shoot about a 300g bullet at subsonic velocity?

Tony

Sure, but the rifle bullet is more aerodynamic. It'll retain velocity better, and have less drop over a given distance. And you can't shoot a 45 Colt out of a semi auto rifle.

[technojock]

It still seems like an answer in search of a question...

Tony

[reddog81]

It still seems like an answer in search of a question...

Tony

Realistically, You could say the same thing about any cartridge developed in the last 110 years.

[technojock]

If that were true, there would be a lot less guns in my safe. 8-)

Tony

[Fitz]

Think i will stick with my 375 Raptor 370 gr powder coat boolits 1 in 10 twist great accuracy out to and past 100 yds brass made from milsurp , I don't see the 1 in 3 twist as being needed.

[technojock]

I've always wanted a .375 H&H or a .416 Rigby but for the life of me I can't explain why.

Tony

[Castaway]

475AR, the point is very few people use a 45 GAP. If a cartridge is good, the popularity will spread and stay with us a few years. Other than from devoted reloaders, you’d have a hard time going to WalMart and buying a box. On another note, it seems you’ve filled the criteria of a heavy subsonic bullet out of a semi auto with your 45 GAP conversion. Maybe you could resurrect it

[475AR]

475AR, the point is very few people use a 45 GAP. If a cartridge is good, the popularity will spread and stay with us a few years. Other than from devoted reloaders, you’d have a hard time going to WalMart and buying a box. On another note, it seems you’ve filled the criteria of a heavy subsonic bullet out of a semi auto with your 45 GAP conversion. Maybe you could resurrect it
I think that marketing types are the casue of cartridges to fail, they pump them up and when people get them and do not perform as advertised then they drop them and the cartridges get a bad rap. Case in point the 41 magnum has been said to be a dead cartridge that won't die, the 44 magnum can do everything the 41 can and do it better. When in fact it is the opposite, the 41 can do everything the 44 can and in most times with bullets of less weight and less recoil.
I don't want to revive the 45 GAP, because if it does become popular then I would have to pay more for brass, and as you mentioned I reload and factory ammo isn't a priority for me.
Another case in point is with the 8.6 Blackout, as has been mentioned by many in this thread it is a solution looking for a problem. BUT if people want to work with it and experiment with it more power to them, and if they enjoy shooting it all the better. As I stated I am not going to jump on the 8.6 bandwagon as I already have a subsonic. 338 that will shoot the same bullets as the 8.6 and use a smaller platform (AR15) and a lot less powder.

[cainttype]

Although I have no use, or interest, in the “8.6 Blackout” I have seen it used.
1) NEVER try to shoot at it’s super-sonic potential through a suppressor without testing the bullet first with the suppressor removed… A factory Winchester 225 grain .338 WILL be particles as it exits the muzzle, and any suppressor will be toast on shot number one…. I know this to be fact! Lol

2) The idea (of course) was delivering a really high sectional density projectile at high RPM to keep it stable at the sub-sonic speeds as long as possible…It actually works, but is extreme.
Special projectiles were developed with this weirdo that basically open/expand into several large blade-like appendages on impact that look wild in ballistic gel, spinning through the gelatin like a big cork-screwing broad-head… slashing giant spinning wound cavities…
I’m sure more than a few were impressed enough by those photos to race out and get in line for an early version.

A buddy shooting it did state that someone had “successfully” used cast at 900 fps, IIRC, without the lead bullet fragmenting.
He also said the report included no accuracy information at those speeds… I suggested that maybe it was because it couldn’t hit paper. ;)

Lastly, lots of ideas that aren’t very good often sell like hot-cakes and outlast their usefulness. I’ll avoid mentioning several so their current fans don’t get their feelings hurt.
Contrastingly, lots of very good ideas never get the attention they deserve and simply slip away. Some of those see a resurgence later and suddenly get lots of favorable attention, from the same people that ignored them originally.

The latest example of a good idea dying, but quickly returning to great fanfare is the PRC line of cartridges… The greatest thing since sliced bread…Precision Rifle Cartridge…
Truth is, they are nothing more than the excellent case design of the Ruger Compact Magnums, that the shooting public at large basically ignored and let “die” in a very short time, being necked to various calibers and finally getting the credit they deserved 15 years ago.

Market success is not always a determining factor in the value of an idea, or the quality of a design.

[sse]

Well said cainttype

[Castinator]

Not looking to start a discussion on the merits of the cartridge.

But of course every chucklehead here did exactly that.

[murf205]

1:3" twist, wow, talk about spin drift.

[Stopsign32v]

That's a VERY expensive semi auto to feed.

No thanks

[technojock]

Any one here actually shoot one yet? If Henry offered one in a single shot with a 4 to 1 twist rate, I'd have a hard time passing it up...

Tony

[J.R.]

It was designed to be accurate out to 300 yards and still retain enough rotational energy to consistently expand. It was taking everything learned from the development and use of the 300 BO and improving upon it.

[J.R.]

Not out to 300 yards. And, as it has a lot of rotational energy, it retains that energy, so has much more energy on target. It’s just rotational rather than plain velocity.

[barrabruce]

Being subsonic wouldn’t the b.c. Of the pointy high speed bullet be pointless.
It probably needs the spin speed to fragment and stay stable but bullets loose very little spin speed by the time they hit something and a round nose would be a more slicker.
The drop difference at range would only be a couple of clicks difference out to 300 at least.

Obviously going for the 500-600 range area.

Personally can’t see any point unless you like to buy expensive hard to get boutiques bullets and need to go right out there.

Have to spot something then back away far enough to justify the expense of a shot.

Be like plinking with a 338 Lapua magnum at 100 yrds

The unwashed heaven in me tells me so.

[MotelAlpha]

I don't post often, but read almost everything here, so,The SAMMI organization is coming out with the specs for the 8.6BLK in a month or so, and they are "supposed" to be regulating the twist at 1:5. This means once they release the specs more folks will be getting onboard just like 300BLK. The 8.6 was specifically developed for "subsonics" and not high velocities. The high /tight twist is supposed to serve two purposes, 1) to help stabilize the larger boolits ,and 2) make one heck of a wound channel....seems to work in both cases.
Happy New Year

[nighthunter]

Has anyone considered casting with zinc for this round? Zinc probably will withstand higher velocities than a lead alloy. I think it would be worth trying.

[barnetmill]

I wonder why for such a fast twist they are not using gain twist rifling.

I assume that the fast twist will give expansion from a low velocity bullet upon striking flesh or other materials. Might have a very erratic path in flesh. Might sort of act like a prop coming off its rotor.

[wmitty]

Correct me if I am wrong on this; I’ll get over it somehow. Won’t high rotational speed accentuate the imbalance of a cast lead alloy projectile to the point that accuracy is destroyed? My thinking has been geared toward slowing the rotational speed to the minimum necessary to stabilize a cast boolit at a useful velocity. Seems like the 2000 rev/second of a 180 grain .30 caliber boolit launched at 2000 fps from a 1 in 12” twist rate is a whole lot more useful to us than a 1000 fps boolit from a 1 in 6” twist spinning at the same rotational speed. Maybe I’m too dense to understand the usefulness of relatively high bc boolits at low velocity. And to increase the rotational speed to 4000 rev./sec. (1 turn in 3” twist rate) simply begs the question “why”?

[jdgabbard]

In case any of you haven't seen the Garand Thumb videos on the 8.6blk, you ought to check out the videos below. The 8.6blk is a VERY impressive round. You can get BCA uppers for like $400... https://www.bearcreekarsenal.com/guns-parts/ar-10/ar-10-complete-upper-assembly/8-6-blackout.html


Here are the videos, I suggest watching both.

https://www.youtube.com/watch?v=ns96O3ZP0qU

https://www.youtube.com/watch?v=_VNTSN4nmEw

[Barry54]

I checked out the Bear Creek uppers. They have the one in three twist as well. I would consider the cartridge if it was one and seven or slower. Why can’t the manufacturers make both?

[jdgabbard]

Because of the design purpose. It's meant to be a suppressed rifle with enough ballistics downrange to be effective at terminating life. Meaning, it needs a big and slow bullet. To do that, you need a big case, and a bigger bullet. To stabilize it, you need a slow twist. It really wasn't designed with cast in mind. But the performance of some of those factory loads is quite impressive....

[barnetmill]

In case any of you haven't seen the Garand Thumb videos on the 8.6blk, you ought to check out the videos below. The 8.6blk is a VERY impressive round. You can get BCA uppers for like $400... https://www.bearcreekarsenal.com/guns-parts/ar-10/ar-10-complete-upper-assembly/8-6-blackout.html


Here are the videos, I suggest watching both.

https://www.youtube.com/watch?v=ns96O3ZP0qU

https://www.youtube.com/watch?v=_VNTSN4nmEw

I have had issues with BCA uppers.

[jdgabbard]

I have had issues with BCA uppers.

What issues? I’m legitimately interesting know, as I’ve been eyeballing buying a few…

[barnetmill]

What issues? I’m legitimately interesting know, as I’ve been eyeballing buying a few…

They would not chamber factory ammo in various chambering. I fixed them by trying out different bolts. 5.56 and 7.62x39 bolts are cheap. I am not sure what it is for 8.6 to get a spare bolt. I purchased my uppers a few years ago and maybe they now bother to change out the reamer when they get worm or to even head space the chamber and bolt. With my experience it was about a 50% failure rate.

[Barry54]

I haven’t gotten an A.R. 10 barrel from them I’ve been happy with. Sent a couple back and got different ones and they were no better. Does anybody want a 20 inch 6.5 Creedmoor barrel? Pay for the shipping and I’ll send it to you.

[Texas by God]

Because of the design purpose. It's meant to be a suppressed rifle with enough ballistics downrange to be effective at terminating life. Meaning, it needs a big and slow bullet. To do that, you need a big case, and a bigger bullet. To stabilize it, you need a slow twist. It really wasn't designed with cast in mind. But the performance of some of those factory loads is quite impressive....

You meant Fast twist, didn’t you?[emoji848]


Sent from my iPhone using Tapatalk

[jdgabbard]

You meant Fast twist, didn’t you?[emoji848]


Sent from my iPhone using Tapatalk

That I did…. Sorry, nap time happened immediately after that comment. I clearly needed it!

[barnetmill]

Because of the design purpose. It's meant to be a suppressed rifle with enough ballistics downrange to be effective at terminating life. Meaning, it needs a big and slow bullet. To do that, you need a big case, and a bigger bullet. To stabilize it, you need a slow twist. It really wasn't designed with cast in mind. But the performance of some of those factory loads is quite impressive....

''it needs a big and slow bullet.'' Big slow bullets have been around for a long time. I have never heard of a 1:3 twist ever being needed or used for stabilizing a long slug.

[elmacgyver0]

I bought a BCA upper in 9mm, a side charging unit that does away with the buffer tube arrangement. Seems to work just fine.
I ordered a right-hand charging lever and received a left-hand unit, deciding I would give it a try as I really did not want the hassle of sending it back.
I like it so I am kind of glad for the mix up.
It was cheap, it works, and I am happy with it.
I cannot comment on any other BCA products as I have no experience with them.

[barnetmill]

I bought a BCA upper in 9mm, a side charging unit that does away with the buffer tube arrangement. Seems to work just fine.
I ordered a right-hand charging lever and received a left-hand unit, deciding I would give it a try as I really did not want the hassle of sending it back.
I like it so I am kind of glad for the mix up.
It was cheap, it works, and I am happy with it.
I cannot comment on any other BCA products as I have no experience with them.

I have gotten my uppers to work, but just not my experiences but those of two others had tight 5.56 chambers. One person was going to grind the bolt face. I do not know that worked or not. But perhaps BCA have since solved that problem. All screws seem tight, barrel extensions are lined up, and so far nothing else. Being over gassed they are, but that can be corrected also. Better overgassed then undergassed relative to fixing it. That is one of the things that I am doing now.

[jdgabbard]

''it needs a big and slow bullet.'' Big slow bullets have been around for a long time. I have never heard of a 1:3 twist ever being needed or used for stabilizing a long slug.

The heavier the bullet, the faster the required twist to stabilize it. Same reason M16s went from 1:9 twist with 55gr to 1:7 twist for 62gr.

The 8.6BLK is sending something on the order of 300gr+ bullets downrange. That's a 33cal bullet weight 300gr+... It absolutely needs a fast twist. You can shoot lighter bullets, and yeah, you could probably get away with a slower twist. But that isn't the purpose of the 8.6blk.

[barnetmill]

The heavier the bullet, the faster the required twist to stabilize it. Same reason M16s went from 1:9 twist with 55gr to 1:7 twist for 62gr.

The 8.6BLK is sending something on the order of 300gr+ bullets downrange. That's a 33cal bullet weight 300gr+... It absolutely needs a fast twist. You can shoot lighter bullets, and yeah, you could probably get away with a slower twist. But that isn't the purpose of the 8.6blk.

What the twist of the 300 whispers with 250 grain pointed bullets.

The longest bullet below was a 240 that was intended for a whisper loading. The 1 in 7 twist in the 5.56 is needed at super long ranges like a 1,000 with heavier supersonic bullets. We are talking about subsonics I believe. I can certainly be wrong about this. The faster 1:3 twist could help a subsonic bullet expand, but more accurate I wonder.

The range of bullets the .300 Blackout and Whisper can digest is impressive. From a 110-grain soft point to a 240-grain match boat tail, you can load anything that will fit the chamber and throat.

328080

[jdgabbard]

What the twist of the 300 whispers with 250 grain pointed bullets.

The longest bullet below was a 240 that was intended for a whisper loading. The 1 in 7 twist in the 5.56 is needed at super long ranges like a 1,000 with heavier supersonic bullets. We are talking about subsonics I believe. I can certainly be wrong about this. The faster 1:3 twist could help a subsonic bullet expand, but more accurate I wonder.

328077

Go look at that second video I shared in the previous post. I believe this is that same bullet (could be wrong though) that they test. Also, Many of the loadings are up around 350gr. They're HEAVY for caliber. And traveling subsonic doesn't help things much.

328079

[Barry54]

It’s a one trick pony with the 1:3 twist. I’m not going to dispute the hype that the super fast twist is more effective on game.

I do believe it is over-stabilized and the nose of the bullet will not follow the arc of the trajectory. Probably nothing noticeable within 200 yards. As produced it likely does what they claim. I can’t afford to feed one premium monolithic bullets though. A 1:7 twist is likely fast enough to stabilize anything currently available and would be more friendly to cheaper cup and core bullets and cast too. Yes, the monolithics probably won’t expand like the photos, if they expand at all.

As cheap as AR barrels are (and easy to swap) and expensive as 338 solids are, it would be worthwhile in my mind to have two barrels in the chambering with different twist rates.

[jdgabbard]

It’s a one trick pony with the 1:3 twist. I’m not going to dispute the hype that the super fast twist is more effective on game.

I do believe it is over-stabilized and the nose of the bullet will not follow the arc of the trajectory. Probably nothing noticeable within 200 yards. As produced it likely does what they claim. I can’t afford to feed one premium monolithic bullets though. A 1:7 twist is likely fast enough to stabilize anything currently available and would be more friendly to cheaper cup and core bullets and cast too. Yes, the monolithics probably won’t expand like the photos, if they expand at all.

As cheap as AR barrels are (and easy to swap) and expensive as 338 solids are, it would be worthwhile in my mind to have two barrels in the chambering with different twist rates.

Well, if you watch the first video, they setup 3x 18" blocks, and it pencils straight through all three of them without slowing down. Along with making comments that one of the guys they talk to said he shoots cape buffalo with that round.... Another round they test is designed to tumble on impact. So, I'd say it depends on the specific bullet being used. The company that created it tested it down to 1:1 Twist, and said there were advantages to even the 1:1 twist. But settled on the 1:3 as it was a good compromised and allowed them to use most off the shelf bullets. Meaning, even at 1:3 Twist most .338 bullets they tested can withstand the rotational forces.

[jdgabbard]

To be clear, I don't know what purpose it really serves outside of a special warfare role. But it is very cool. I personally don't have any need for it. But if money wasn't an issue, I'd probably own one...

[Shanghai Jack]

That caliber really interested me when I first saw it. I know I will need to be patient, and wait for more main stream manufacturers to offer rifles chambered in it. I know very little about it. Is there a parent case that in can be formed from?

10mm magnum

[Barry54]

It’s the modern version of the 338 Whisper JD Jones created. Just like the 300 Whisper he created. He kept them proprietary and the chamber leade got changed several thousandths. It’s been renamed 300 Blackout and went mainstream.

Sadly most blackout owners/users have probably never heard of JD Jones or all the Whisper cartridges he created. There’s even a Mini Whisper off the 7.62x25 case.

[barnetmill]

I invested 30 minutes on the two 20 minutes videos. I saw no demonstration that the astounding twist rate was needed for accuracy, but it definitely has a role in terminal ballistics. A long pointed fmj will zip through multiple gel blocks and not deviate. Hollow pointed expanding ammunition turned into a buzz saw.
For segments that I watched I do not see any grouping experiments. Seems to be quiet, but within 100 yards in the country side I would hear the report and know that it is at least an air rifle if not more. It is over a 100 decibels. .22 CCI quiet ammo from a long barrel is about 80 DB w/o any required nfa paper work for a silencer on the barrel.