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5.56, 300 aac sbr question

Mr_Brass

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Full Member
Minuteman
Apr 10, 2010
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45x90 WI.
Looking at getting into the sbr game but not sure about buffers and all that jazz can y'all educate me was looking at doing a 5.56 11.5 and a 300 blkout in 10.5 wanna make sure I get good cycles without beating my gun to hell and back
 
I haven't had any problems running a 8.5" 300blackout (subsonic only) and a 7.5" 5.56 with a standard carbine spring and H2 buffer.
 
My 10.5" LMT 5.56 and my 9" AAC 300BLK runs with an H buffer and an H2 with standard carbine spring both suppressed and unsuppressed. Suppressed the 10.5" 5.56 really could use an H3, but the H2 runs it just fine to the point that I am not going to change it.
 
Looking at getting into the sbr game but not sure about buffers and all that jazz can y'all educate me was looking at doing a 5.56 11.5 and a 300 blkout in 10.5 wanna make sure I get good cycles without beating my gun to hell and back

We've seen some folks have a hard time with 300 Blk, but done correctly they run just fine. It really is a neat round. Consider sticking with pistol length gas and keep in mind that the conventional 5.56 AR thinking won't all be the same with the 300blk.

On the 5.56 you might take a look at the WAR upper. I'm running two of them personally and we are getting good results with them across the board. Keeps cleaner and it is quieter. I'm impressed with the design and prefer it to the other choices out there. I've been running a 10.5" bbl on a WAR upper pretty hard and it is doing great.

On my 10.5" 5.56 I'm running an H2 and it is running properly. Some of this depends on a few variables so it can be a little different from one build to another. Really helps if you have a few to try, or if you have buddies that have some different buffers for you to test on.
 
We've seen some folks have a hard time with 300 Blk

i.e. cheap bastards who try to run a 99 dollar barrel and wonder why the gun dont run:D. Or they have some weird ass ultra heavy spring/buffer combo and miracle of miracles when they swap to the recommended standard GI spring and C or H2 buffer(depending on barrel length), the gun miraculously starts to run right.

AAC and Noveske are more expensive, but they also run with no issues so I feel that its money well spent.

Ive been interested to try a Palmetto 300BLK barrel as well as the ones from Black Hole Weaponry as their reputation for their 5.56 barrels is pretty decent. Most of the rest of the brands seem to be hit or miss with more miss's than hits IMO.
 
i.e. cheap bastards who try to run a 99 dollar barrel and wonder why the gun dont run:D. Or they have some weird ass ultra heavy spring/buffer combo and miracle of miracles when they swap to the recommended standard GI spring and C or H2 buffer(depending on barrel length), the gun miraculously starts to run right.

AAC and Noveske are more expensive, but they also run with no issues so I feel that its money well spent.

Ive been interested to try a Palmetto 300BLK barrel as well as the ones from Black Hole Weaponry as their reputation for their 5.56 barrels is pretty decent. Most of the rest of the brands seem to be hit or miss with more miss's than hits IMO.


i was going to use AR stoner barrels for the 300 heard they were good
 
i was going to use AR stoner barrels for the 300 heard they were good

I don't have any experience with them just reading on 300blktalk about them. I don't think they are terrible just be prepared to open the gas port up to .125, hell do it before you build the upper. You can't over gas a carbine length gun on the 300blk. The other thing just looking at the specs of the ar stoner barrel is the 8 twist, I prefer the 7 twist.

It's realistically a 150 price difference between the ar stoner and noveske or aac when you take into account aac and noveske supply gas blocks and tubes. They also stand behind their product.

Imo it's money well spent but I typically gravitate towards the higher end stuff.

If I was building a blaster and didn't mind tinkering with things and knew what I was doing, the cheaper barrel would probably be ok.
 
I have an SBR I switch between a 12.5" 5.56 upper and a 10" 300 BLK and bith have run perfectly with the H2 buffer. Recebtly bought a Vltor A5 extension with the standard weight A5 buffer and spring and it runs perfectly too, but is SLIGHTLY softer shooting suppressed.
 
On my 11.5 SBR I run a H3 buffer, regular carbine spring, and m16 profile bolt carrier. Never had any issues when using wolf/tula all the way to M193.
 
I've always ran this heavy bastard in my 8" 300 BLK:

Counterweight Buffer | Brownells

My supersonic load is hard enough on the rifle as it is, and I believe through simple physics that the heavier buffer reduces some of the beating that the rifle takes. Sub's cycle just fine, though I rarely use them.