Best buffer for AAC 9"

[drozdws6]

So I'm finishing up my 300 BLK build and needed some help on what buffer to use. My AAC 762SDN-6 is still several month down the road. So I need a buffer that going to function well with supersonic rounds. I am running the AAC 9" blackout barrel. Also I planned on loading up some 110gr.-125gr. rounds if this matters.

Thanks

[JasonAAC]

So I'm finishing up my 300 BLK build and needed some help on what buffer to use. My AAC 762SDN-6 is still several month down the road. So I need a buffer that going to function well with supersonic rounds. I am running the AAC 9" blackout barrel. Also I planned on loading up some 110gr.-125gr. rounds if this matters.

Thanks

Our 9" uppers are setup to run with H2 buffers. that's where i'd start with yours.

[300Blk]

Yes, H2.

And our 16 inch uppers are best with H buffers.

[NordicG3K]

I was already running a Spike's ST-T2 heavy buffer in my registered lower and when I used my 9" Blackout upper it wouldn't lock the bolt back on an empty mag. Going to a regular carbine buffer it now runs fine, but the only load I've put through it so far is a 147gn FMJ over 15.5gns of H110 which may be a bit on the light side.

[300Blk]

I was already running a Spike's ST-T2 heavy buffer in my registered lower and when I used my 9" Blackout upper it wouldn't lock the bolt back on an empty mag. Going to a regular carbine buffer it now runs fine, but the only load I've put through it so far is a 147gn FMJ over 15.5gns of H110 which may be a bit on the light side.

That is a very light load. I would look into 2-3 more grains of powder.

130 grams is the weight of an H2 buffer.

http://www.silencertalk.com/forum/viewtopic.php?t=42479

[imyomama]

I was already running a Spike's ST-T2 heavy buffer in my registered lower and when I used my 9" Blackout upper it wouldn't lock the bolt back on an empty mag. Going to a regular carbine buffer it now runs fine, but the only load I've put through it so far is a 147gn FMJ over 15.5gns of H110 which may be a bit on the light side.

got exact same buffer setup on my 9" ar blk .. and no problems from either 125's to 220 smk subs ... i'd say it's your load

http://www.youtube.com/watch?v=2UehOw94yc0

[300Blk]

I should also add that the AAC 9 inch is also designed to work with the HK-416 buffer, which is powdered Tungsten. I am not sure if the Spikes is as heavy though - but should be close enough.

[Tom12.7]

I'm not surprised about the different buffer weights from different manufacturers. I have a H2 buffer that weighs in about halfway between my Colt H and Colt H2 buffers. I bet it's a CMT. What are the identifying marks on the CMT?
Thanks,
Tom

[NordicG3K]

The Spike's buffer also uses powdered tungsten and weighs 4.3 ozs (122 grams). I use the same buffer in another lower for my 12.5" 6.5 Grendel and it works great.

Thanks for the input on my load. I had a feeling it was light. I started out real low and increased gradually until it was ejecting and feeding fine. The only issue was locking open on an empty mag. I've started playing with the 110gn V-Max and I'll have to try the Spike's buffer again.