300 ACC Blackout

Rugbier · Dec 29, 2011

Since apparently all I need to do is change the barrel to convert an AR15 .556 to a 300 ACC I was wondering the following:

A - Are they available with a 1/2 -28 thread ( so I can use my 9mm can ) ?

B - Are they available in 11.5" ( I have a shorty I could change the barrel ) ?

C - Any of our local suspect IP carry these items in the above conditions ?

D - Please feel free to add recommendations

Thanks

mikec · Dec 29, 2011

AAC shows a 9" barrel that has 5/8-24 threading. Lots of info to dig through. Best i can come up with short term.

razorV23 · Dec 29, 2011

Only threads I have seen are 5/8x24, I ordered an adapter from TROS to use my 45 can on my 10" barrel.

I think 1/2x28 threads are cutting it close for a .30 bullet

Russ D · Dec 29, 2011

I believe Wilson Combat makes an 11.5 but its on backorder.

rsilvers · Dec 29, 2011

1/2-28 threads are possible on a 30 cal, but no one does it. 9mm cans will get hot very fast with subsonic ammo, and cannot be used with supersonic ammo.

AAC makes a 12.5 inch upper.

Rugbier · Dec 30, 2011

rsilvers said:
1/2-28 threads are possible on a 30 cal, but no one does it. 9mm cans will get hot very fast with subsonic ammo, and cannot be used with supersonic ammo.

AAC makes a 12.5 inch upper.

Educate me if you will...

Why will you use supersonic ammo with a suppressor, isn't counter-productive ?

I am thinking to build the 300 ACC as my .556 can can't quiet too much my AR and shooting supersonic will be the same as my .556 suppressed

am I missing something?

Kingjamez · Dec 30, 2011

Rugbier said:
Educate me if you will...

Why will you use supersonic ammo with a suppressor, isn't counter-productive ?

I am thinking to build the 300 ACC as my .556 can can't quiet too much my AR and shooting supersonic will be the same as my .556 suppressed

am I missing something?

It is not counter productive at all to shoot supersonic through a suppressor. The sonic boom is certainly present, but the rest of the blast is much more palatable. The recoil is reduced, and the overall shock wave is sent down range instead of at you or your buddies.

-Jim

Les Gawlik · Dec 30, 2011

I've been doing a lot of reading and it seems like 300BLK is a great innovation. The only thing I've not been able to find is the source of the name. Anyone know?

Kingjamez · Dec 30, 2011

AAC = Advanced Armament Corp, the company that worked to modify and put the .300 whisper up for SAAMI "certification". Blackout is a name on a few of their products, and is a catchy description for a round designed for sub sonic performance.... then again so is whisper.

-Jim

vette97 · Dec 30, 2011

My interest in this round is starting to peak!

Les Gawlik · Dec 30, 2011

From what I've read, the AF was testing a round like this in the late 60's. I can't believe the military hasn't been all over this for decades. It sounds like the perfect blend of AR accuracy with (better than) AK knockdown.

Russ D · Dec 30, 2011

vette97 said:
My interest in this round is starting to peak!

All the cool kids have one. :cool:

xtreme43s10 · Dec 30, 2011

Russ D said:
All the cool kids have one.

, I just wish I didn't wait so long to build one.

NateTheShake · Jan 2, 2012

Rugbier said:
A - Are they available with a 1/2 -28 thread ( so I can use my 9mm can ) ?

Most if not all available barrels are threaded for 5/8X24 (the common .308 threading for QD flash hiders). There are conversion adapters for 5/8X24->1/2X28 HOWEVER I would be very cautious shooting these through a can rated for 9mm pressures. At best maybe the subsonic loads would do alright, but I'd still be nervous about the difference in pressure and the possible damage to the can. It might work, but I sure as hell won't be the first to try it.

I am planning a 300BLK build and I'm planning to go with the YHM Phantom 7.62 QD can for that as well as several other platforms I already own.

Up until now I haven't been interested in alternate AR calibers. 6.5 and 6.8 as well as many others require almost a full re-build of the platform. 7.62X39 doesn't seem to work very well and again requires a different bolt, barrel, and magazine. 300BLK is a barrel change. That's it. Everything else is good to go and carries over from every other 5.56 AR. It's certainly not a long range cartridge, but at ranges </= 200 meters it should offer a good improvement over the 5.56 with very little cost to change over. Plus the brass is formed from standard 5.56 cases and the bullets are standard 308. Ammo manufacturers and handloaders should have no problems retooling to produce these easily from existing (and plentiful) components.

FHJ69 · Jan 2, 2012

Andy at Engage has an AAC 10.5" barrel mounted to a Knights Armament upper and looks very sweet. 300 Blackout. AAC designed the suppressor for the round and I believe it's a 762SDN-6. I currently have a SBR lower in the ATF slow lane for a 300 build. Lots of good info on this round. Other then cost (which can be negated by reloading) it seems perfect for the AR platform. JMHO.

Rugbier · Jan 2, 2012

FHJ69 said:
Andy at Engage has an AAC 10.5" barrel mounted to a Knights Armament upper and looks very sweet. 300 Blackout. AAC designed the suppressor for the round and I believe it's a 762SDN-6. I currently have a SBR lower in the ATF slow lane for a 300 build. Lots of good info on this round. Other then cost (which can be negated by reloading) it seems perfect for the AR platform. JMHO.

Is Andy's toy or for sale?

EngageSmith · Jan 2, 2012

Rugbier said:
Is Andy's toy or for sale?

Nope, but we can help you find an upper. I built a 16" .300-221 (wildcat of the proprietary .300 Whisper original) rifle when I was in gunsmith school, and it can fire .300 BLK as well. It is VERY quiet. We shot an assortment of .300 BLK rifles (Andy's with the AAC 762-SD-N6 can, mine with a YHM 7.62 Phantom can, Andy's Micro-7) vs. an MP5SD6 for comparison. They were all about the same noise level, just different sound pitch.

The action working on these weapons is louder than the muzzle report when suppressed.

Rugbier · Jan 2, 2012

Garret,

We can talk when I see you this week ( assuming you got that silly spring issue done )
I want to shoot suppressed through a 9mm can ( at least that is possible and common on blackout forum ).
let me know if you know of a place to get a shorty barrel with 1/2-28 thread if you have the time

Thanks

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