How to pick the right buffer?

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Zedhound

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how does one pick the best buffer for ar15s/ar9s without buying a bunch you don't need or that wont work?

my 300 doesn't cycle sometimes cause I shoot subs
and i've heard if you don't have enough weight in ar9s that you can break the bcg after awhile. in fact I think someone here recently did so.

does anyone sell an adjustable weight buffer?

thanks
 
Your issue may be more related to your gas port size than anything else. Who's the manufacturer? It's common for 300blk to not reliably cycle both if the wrong combination of gas port size and gas system length is used.

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For an AR-9 PCC, nothing seems to beat the Blitzkreig 9mm Hydraulic buffer. It is magic in an AR-9! Buy one, install, and shoot.
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Blitzkrieg AR-15 9mm Hydraulic Buffer
 
For an AR-9 PCC, nothing seems to beat the Blitzkreig 9mm Hydraulic buffer. It is magic in an AR-9! Buy one, install, and shoot.
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Blitzkrieg AR-15 9mm Hydraulic Buffer


I've broken 2 AR9 bolts.

I solved the problem at first with an 11oz buffer from heavybuffers.com and a .308 spring. I just picked up a Blitzkreig that I have yet to try out.

But to answer your question...you do just need to try a bunch of different buffer/spring setups to figure it out. If you were near me I'd lend you my drawer full of various weight and length buffers. Essentially you want to slow down that blowback operation as much as possible while still having reliable ejection and LRBHO.
 
"try a bunch of different buffer/spring setups to figure it out"

The hydraulic buffer eliminates this procedure^^^^^^^^^^ Install and forget.


KynShot makes all kinds of industrial hydraulic buffers for different applications in industry. They make hydraulic buffers for AR-15 and AR-10 rifle platforms. They also contract manufacture the 9mm buffer for Blitzkreig. I like a light bolt carrier, short stroke, a hydraulic buffer and a stock AR-10 rifle length spring. The bolt carrier needs to stop once it clears the ejection port in the upper receiver. I want the gun to cycle fast (return to battery) and shoot soft.
 
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I've broken 2 AR9 bolts.

I solved the problem at first with an 11oz buffer from heavybuffers.com and a .308 spring. I just picked up a Blitzkreig that I have yet to try out.

But to answer your question...you do just need to try a bunch of different buffer/spring setups to figure it out. If you were near me I'd lend you my drawer full of various weight and length buffers. Essentially you want to slow down that blowback operation as much as possible while still having reliable ejection and LRBHO.


I wish someone was close to me with one of these hydraulic buffers so I can try before I buy
 
If it's 300BLK and you aren't getting reliable cycling with subsonics, it may be that you have too much reciprocating mass, not too little. If you're running a full auto bolt carrier, try switching to semi-auto. If you have a heavier H, H2, or H3 buffer, try stepping down to a standard Carbine-weight buffer.

On my SBR, I actually wound up taking one of the three steel weights out of a Carbine-weight buffer and replacing it with a wood dowel to reduce the mass even more.

Also, @Wahoo95 is correct that your gas port may be undersized. Mine came at 0.125," and aside from needing to reduce the mass slightly, it's worked fine.
 
I shot my ar9 yesterday, and I was paying more attention to the sound of the buffer and the action moving. is it terribly long... no. can I reduce it... yes.

does anyone use a spacer in their AR9? does it make much of a difference or should I just get a heavier spring?
 
I've used the Vltor A5H3 and A5H4 buffers. They are longer and heavier than regular cabine buffers and fit Ar9 perfectly. They work fine. I tried the Spikes ST-9X. It was a little too heavy for the action to cycle reliably on my build. I'm also using a H2 buffer with a short piece of thick walled tubing as spacer. I don't shoot my Ar9s enough to say whether any of these configurations will save the BCGs though.
 
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