What type buffer

[bitman]

Howdy. Putting parts together for a 300 blackout pistol build ... Probably use a 10.5 inch barrel.

I've built several ARs but this is my first pistol and first Blackout.

What type buffer and spring should I use? I understand there is an issue with ability to cycle if you use a normal carbine buffer/spring with a 5.56 pistol.

Thanks in advance for any help.

Dave


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[J_Dub_503]

I would imagine a standard carbine action spring (http://www.bravocompanyusa.com/Carbine-Action-Spring-p/spring%20carbine%20action.htm) and a H2 Buffer (http://www.bravocompanyusa.com/H2-Carbine-Buffer-p/buffer%20carbine%20h2.htm)would be the optimal set-up.

[J_Dub_503]

Just found some literature from AAC


ACTION SPRING/BUFFER
Use either the standard USGI M4 or the HK 416 spring. For buffers, select a 4.6 oz (130 gm) H2 or an HK-416 buffer-
though a 5.5 oz (155 gm) H3 buffer may be a good choice if you don’t intend to shoot subsonic without a sound
suppressor or typically shoot supersonic ammo. Do not use a solid 9mm buffer as it may cause bolt bounce

http://300aacblackout.com/resources/300BLK-AACUpper-Manual-Sep2010.pdf

[bitman]

Terrific, thank you.

Dave


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[rsilvers]

AAC uses H2 buffers for all 300 BLK SBRs, but other makers could have designed their upper around any buffer.

[Quiet Riot]

My 8" Noveske pistol has a Spikes T2 buffer. It cycles everything but subsonic unsuppressed just great, and that is what Noveske says to expect of their 300 BLK barrels.

[doctorfireant]

I just finished a 300 Blackout build with a Noveske 10 inch barrel. Since I am waiting on the SBR stamp I had to go with a pistol configuration.

I used all new parts in the build and chose a heavy buffer.

At the range, I had a problem with the bolt staying open after the last round. Rem UMC 115 gr. was the round being used.

I changed to a standard buffer and I did not have any more problems. The bolt stayed open on the last round.

I figure part of the problem could have been that all of the parts were just breaking in and I may need to go back to the heavy buffer as I put more rounds through the rifle and the parts settle in. We will see.