8.6 Blackout! WHAT!!!

Let me (Google) guess... .308 Win is the parent case?

Its a 338 Federal (a 308 necked up to accept a .338 bullet) with the shoulder set back to allow longer heavy bullets to maximize subsonic performance and is size to work in AR-10 (308) length magazine/actions.

Wait til you see what the barrel twist is.

troy fairweather said:

Wait til you see what the barrel twist is.

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Holy Cow!!!!! 1:3 Twist !!!!

I think it’s a chopped up 6.5 creedmoor necked for .338

Mark_Mark said:

Any guess on the Parent Case?

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It’s brother? At least a cousin…

With a twist that fast (1:3) its might be hard to use some of the pre-slitted expanding all copper bullets. I have seen some of the all copper sub-sonic bullet open in flight when fired in a 1:3 twist 300 BO. It going to be interesting to see if this new cartridge has the same issue. I have a 1:5 twist barrel in 300 BO that has not had an issue but 1:3 is going to make'em spin for sure.

dredd said:

Holy Cow!!!!! 1:3 Twist !!!!

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Whoa. Thats fast. Like really fast. I wonder if its instant or gain-twist. Seems like one application that would really benefit from even a mild implementation of gain-twist. Start it at 1 in 9" and ramp it up from there.

Ive never heard of anything faster than 1 in 7", but i have not dabbled in the subsonic world.

I was watching some videos about this, glad to see some discussion. Definitely an odd bird. Sounds like they are pushing up to 300 grain projectiles, and the shot show coverage made it sound like they were trying to use the rotational energy from that crazy fast twist to improve the terminal performance (no sure how that works even).

Thinking outside the box for sure, interested to see where that leads. Who's going to go first...?

This might be a cartridge development that is actually new territory, and not just repackaging of previous ballistic performance while exclaiming that it's something unique and special (looking at you 6.5mm Manbun, 6mm ARC and 350 Legend). The military and Winchester were at least intellectually honest about the 7.62x51mm NATO/.308 Win attempting to achieve .30-06 performance out of the shorter case.

A 300 gr .338 bullet at ~1000 fps is not something I can find that has been previously done to any commercial extent. However, I suspect supersonic loads will probably be close to .33 Winchester performance.

1:3… do they still call it rifling or at that point do they call it threading. Seems a bit too far into subsonic territory for my tastes.

One article I read said it was more threaded than rifled, and the picture sure seemed to confirm.

It also didn't look like gain-twist, but pictures can be misleading.

Zahn said:

One article I read said it was more threaded than rifled, and the picture sure seemed to confirm.

It also didn't look like gain-twist, but pictures can be misleading.

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I believe I saw the same picture.
It looked like the Acme Threads on a Screw Jack.

My imagination pictures the rifling stripping/shaving the bullet, rather than convincing it to twist.

However, I do not have any education in this field to back up my imagination.

1:3" twist definitely doesn't sound cast bullet friendly.

Serious question. With twist that aggressive, would it not be exceptionally hard to push out a squib?

Don't load it HOT....or you will be picking up pieces......

Stack this cartridge in the bin with the new 30 as uninterested.