8.6 Blackout

[sigstroker]

This looks pretty cool, it's the big brother to the .300 Blackout. Basically a 6.5 Creedmoor case expanded for a .338 bullet, I think. At the pace it's been going, my form will be approved for the 46 Hybrid before the ammo and guns get on the market. Maybe that's good though.

It would be cool to be able to kill a cape buff with a 12" short action silenced gun. Maybe SIG will chamber their Cross in it and really piss off Brittingham.

[Tommy Gun]

Which powder is it calling for? Can I stick with my 1680 or 2520?

[ar15barrels]

338 whisper has been around 20 years or more.
7mm BR case necked up to 0.338.
Fits into any 308 mag and has more than enough powder capacity for subsonic loads with any available 338 bullet.
I'm not sure what you gain when going to a larger case capacity when the whole point of the cartridge is heavy subsonic bullets.
The more powder you burn, the more gas you have to deal with in the can...

I have a set of sizing dies I had made 15 years ago to take 7mm BR brass up to 30, 338 and 35 calibers.

[hermosabeach]

Why not .458 socom

Tons of .458 projectiles

[Epaphroditus]

Shoot a Cape buff with that is just foreplay to the biggest ream job of your life.

[12Ga Hunter]

I'm not sure what you gain

Not you, they... they gain money

Why not .458 socom

How are they going to feed their families? See above

[sigstroker]

Shoot a Cape buff with that is just foreplay to the biggest ream job of your life.

Maybe. With 300 grain bullets you might get good penetration even at 1000 fps. Plus, they are seeing weird results with very fast twists, like 1 in 3. Brittingham hinted at "rotational energy" adding to the destructiveness. You can't just go by velocity energy numbers. In gelatin tests, the fast twists were causing huge amounts of damage compared to normal twist rates with the same bullets. The good news for kalis is most of the development is with all copper bullets because traditional jacketed lead bullets fly apart at high twist rate.

[LynnJr]

In a 3 twist barrel at 1000 fps the rotation would be 240,000 rpm.
In a 9.36 twist barrel at 3000 fps the rotation would be 230000+ rpm so not much of a difference in centripetal force.
On the larger case capacity it might be to use a slower burning powder like Trailboss?
In a 300 you can't get enough into the case to get consistent velocities.

[stjefferson]

Doesn't cape buffalo hunting require .375 or 9.3mm or larger caliber?

[k1dude]

Doesn't cape buffalo hunting require .375 or 9.3mm or larger caliber?

IIRC, yes.

[AGGRO]

Shoot a Cape buff with that is just foreplay to the biggest ream job of your life.

Might get lucky for a side shot and not hit a rib or gristle. Otherwise better be a tree close by.

[sigstroker]

In a 3 twist barrel at 1000 fps the rotation would be 240,000 rpm.
In a 9.36 twist barrel at 3000 fps the rotation would be 230000+ rpm so not much of a difference in centripetal force.
On the larger case capacity it might be to use a slower burning powder like Trailboss?
In a 300 you can't get enough into the case to get consistent velocities.

Supersonics are over 2500 fps. I haven't seen any mention of powders being used.

[BillyMays]

In a 3 twist barrel at 1000 fps the rotation would be 240,000 rpm.
In a 9.36 twist barrel at 3000 fps the rotation would be 230000+ rpm so not much of a difference in centripetal force.

This is assuming the mass of the projectiles is the same. If two projectiles of equal mass hit an object, but one is traveling 3000fps and one is traveling 1000fps, you would expect the faster projectile to penetrate deeper because it has higher kinetic energy. Now consider two projectiles with equal penetration (and shape) but different speeds- the slower projectile must be heavier to penetrate the same distance. This heavier projectile would have more angular momentum than a similar sized lighter projectile at equal RPM, so it would transfer more rotational energy. My thought is that because the bullet has higher angular momentum and low entry speed, when it hits a target it more quickly begins to tumble? I have no idea if this is true. It also doesn't take into account bullet shape or stability, which I think could have a much greater effect- as seen in .223 wounds.

Anyways just my ramblings... I'm sure I've missed something so please correct me

[LynnJr]

I think I only mentioned the bullets rpm which doesn't take mass into question? Or where you referencing centripetal force which does? I like to use like units to keep perspective.
In the video he keeps mentioning 300 blackout which was in existence as 300 whisper for years before the name change.
You would think all the bugs he mentions would have been worked out?

[sigstroker]

The Whisper was never a SAAMI cartridge and apparently it had bugs.