300 Aac Blackout (300blk)

[robpiat]

Originally Posted by robrob

Looks like a really original idea they came up with. Not.

Merchandising!!!!

[TCCrewchief76]

...and may the Schwartz be with youuuuuuuuueeeeeeeeuuuuuuuuuueeeeeeeeeeeuuuuuuuuuu .....

[Scalce]

Good for them for bringing it to market.

Nobody else submitted the caliber to SAAMI.

I view this as a good thing.

[rsilvers]

If you load your own ammo, pay special attention to all of the normal safety practices. Recommended powder for most supersonic loads is Hodgdon H110.

For subsonic, there are special requirements and nearly all published loads are non-optimal for the 300 BLK upper. Many existing loads were developed for Thompson Center® single-shot pistols, or for ARs by people not aware of the magazine limitations. These loads pay no attention to automatic rifle function and should not be used. Look for a load which results in a cyclic rate of 700 rpm or more. AA1680 is recommended because its bulk density matches the case capacity and it will generate enough gas pressure to cycle the weapon.


Suggested subsonic load:

• R-P 300 AAC BLACKOUT brass
• Remington 7.5 primers
• 11.2 grains of AA 1680 powder
• Case length is 1.368 +0.000 -0.020
• Sierra 220 MK loaded to 2.089 OAL (this length is optimal for reliable feeding from USGI magazines)
• Chamber pressure 21,100 psi.

[alorton]

With a case length of 1.348" to 1.368" it sounds exactly like a 300 Whisper / 300-221 / 300 Fireball with a trim to length of 1.355". I'm assuming since they recommend AA1680 as the subsonic powder that the system uses a carbine length gas tube instead the pistol length. That is unfortunate as the pistol length has proven to be more versatile when switching back and forth between subsonic and supersonic.

As for the magazine problems caused by the bullet diameter that isn't anything new with AR shooters. I've found that a Pmag with the side rib removed is the best solution as opposed to loading ammo to a specific length. This also works well with my 7.62x40 which can't rely on overall length as the case is too long to allow such short loading.

Overall, I don't see anything new here. That said, I think it will be good for the cartridge family to have a SAAMI approved chamber and solid factory backing. I'm still waiting to see if the ammo is interchangable between the Blackout and the Whisper. From what I have read I suspect it may be.

[Hoser]

I think this is a good thing for the industry.

If JDJ had not played I have a secret for so long, the Whisper would have been standardized long ago.

The more people using the 300 Blackout / 300 Whisper the better.

Who knows, we might see some factory R-700s coming out. And a registered SBR out of the factory isnt a bad thing. No need to engrave it.

I am looking forward to seeing it out there.

[robpiat]

Originally Posted by Hoser

I think this is a good thing for the industry.

If JDJ had not played I have a secret for so long, the Whisper would have been standardized long ago.

The more people using the 300 Blackout / 300 Whisper the better.

Who knows, we might see some factory R-700s coming out. And a registered SBR out of the factory isnt a bad thing. No need to engrave it.

I am looking forward to seeing it out there.

+1 . At some point He decided that he would rather have 100% of a small niche than 10-15% of a big pie. My guess is that JDJ had been approached a few times by manufacturers and was too high on licensing cost.

[rsilvers]

http://www.silencertalk.com/forum/vi...?f=128&t=64797

[carcass]

I realize this is a somewhat older thread but I thought I'd ask here.

Originally Posted by rsilvers

Suggested subsonic load:

• R-P 300 AAC BLACKOUT brass
• Remington 7.5 primers
• 11.2 grains of AA 1680 powder
• Case length is 1.368 +0.000 -0.020
• Sierra 220 MK loaded to 2.089 OAL (this length is optimal for reliable feeding from USGI magazines)
• Chamber pressure 21,100 psi.

What barrel length will result in this being subsonic? I have a 7.5" barrel that I chambered for "300 Fireball" or whatever PTG calls their reamer, and I have good reliability with subsonic operation and F/A cycling in an M4 (carbine stock tube with standard recoil buffer) with 9.2 grains of Lilgun, 1.085 OAL, with a chamber pressure of about 33kpsig.

I don't have any 1680 lying around but would like to try this load, but only if it'll work in my short barrel on F/A. BTW, Quickload calculates my load to result in about 8700 psig bore pressure at the gas port position, which is just enough to allow reliable operation. QL calculates your listed load at 8500 psig, but with lower efficiency of powder burn (80% vs 97%). The additional mass of powder (gas) at that lower pressure may provide enough momentum to operate the action. The weird thing is that you state chamber pressure of your load at 21.1kpsig, but QL calculates it at 39kpsig. Any idea what the discrepancy is? Is QL not good at calculating at these relatively small case volumes?

Thanks for any info, and I hope I haven't missed an answer to this that someone already posted.

[rsilvers]

A1680 will cycle far more easily than Lil-Gun at the same bullet velocity.

QuickLoad with the 300-221 chamber?

300 AAC BLACKOUT has lower pressure than 300-221. The longer throat makes it act as if it had a larger powder capacity.

You need a chronograph and have to set the powder to be in the 950-1020 range with your upper.


Suggested subsonic load:

• R-P 300 AAC BLACKOUT brass
• Remington 7.5 primers
• 11.2 - 11.6 grains of A1680 powder (Adjust powder charge as needed. Factory ammo is 1010 fps for 16" barrel)
• Case length is 1.368 +0.000 -0.020
• Sierra 220 MK loaded to 2.089 OAL (this length is optimal for reliable feeding from USGI magazines)
• Chamber pressure 21,100 psi.