Buffer for 6.8 and 5.56 Uppers

[daved]

I'm putting together a lower to be used with two uppers, 6.8 and 5.56, both with 16"barrel/mid length gas systems. Can I use the same buffer for both or do I need to change out the buffers when I change the uppers? In either case (one for both uppers or one for each upper), which buffers would be appropriate? Thanks for your input.

[mark5pt56]

My experience is with the 6.5 and 5.56 in middy's. I have an h buffer in my 6.5 and have run everything from standard, H, 9mm and rifle in various 5.56 middy's with no issues using PMC, XM193 and AE ammo. I'll have a BCM middy soon and will see how she works this way.

I've been told that the H and heavier buffers won't work--

[SeriousStudent]

I believe that Grant posted in the BCM middy thread that an H buffer would work well. I have a BCM middy upper on the way, and will be testing that theory soon.

(Thanks, Grant and Paul! :D)

If I got that wrong, I have a regular carbine buffer to try out. But I'll definitely try the H buffer first.

[daved]

My experience is with the 6.5 and 5.56 in middy's. I have an h buffer in my 6.5 and have run everything from standard, H, 9mm and rifle in various 5.56 middy's with no issues using PMC, XM193 and AE ammo. I'll have a BCM middy soon and will see how she works this way.

I've been told that the H and heavier buffers won't work--

I'm afraid I don't follow - the h buffer in your 6.5 works without issue but "H and heavier buffers won't work". :confused: Are "h" and "H" two different buffer weights?

My gut tells me that H is probably the way to go with both the 6.8SPC and 5.56 middy but would appreciate clarification.

[mark5pt56]

I didn't capitalize the "H" I'm saying that they both work fine for me. There was a previous thread some time ago where it was posted that the middy's won't run on the H or heavier buffers.

[daved]

Thanks for the clarification - I thought the "h" might be light "H" or another designation for the standard carbine buffer.

[rightwingmaniac]

my lwrc 6.8 m6a2 srt came with a h2 buffer.

[daved]

Hum-m-m, would the gas piston system change the buffer requirements?

[mark5pt56]

Hum-m-m, would the gas piston system change the buffer requirements?


ADC recommends the H2 on his PD15 uppers as well. Although I tested it with all buffers and it still worked fine.