I've picked an OEM BCM upper with 18" barrel and LaRue floating rail with a pinned gas block. This was a BCM built upper, it's a few years old but looks unused. I want to put in on an LMT carbine lower that I've got.
I'm unsure which buffer would be appropriate. An H3?
I'd appreciate an informed suggestion.
(My search didn't turn up anything)
TIA
If using a carbine RE, an H or H2 buffer with a known quality standard carbine spring or Sprinco blue spring would be a good place to start.
In my 18 incher I run the standard carbine buffer and spring that came with the Magpul Moe stock I put on.
Only 305 rounds down the pipe thus far, but I can say it has had no malfunctions, runs very smoothly, with everything I've put through it-XM193. M855, my own loads, crappy Tulammo, and others.
Ejects back out right at around 3-4 o'clock.
I am assuming rifle length gas tube, the regular buffer should be fine. Given the rifle gas tube allows the longest dwell time, there shouldn’t be any need for extra mass on the buffer. It’s just added reciprocating mass at that point.
Yeah, forgot about that, it has a rifle length gas system.
If you're using a carbine buffer tube; H2 and I'd probably go Springco Blue spring too.
I might have one or both lying around if you're in need.
One more thought on the issue. 20$ on Amazon you can buy 3 tungsten buffer weights. With those and a regular carbine buffer you can make a h1, h2, or h3. Allows you to mess around with different buffer weights and see which runs best.
Canada runs the C7A2 20" barrel with rifle length gas system and the 4 position adjustable carbine stock. They use the H2 buffer.
I'm wondering if the only reason they use heavier buffers is to prevent bolt-bounce during full auto/3rnd burst firing.
FWIW Bravo Company Manufacturing's website list the RECCE 18 rifle as having a rifle length gas system and an H buffer in it's collapsible stock. I'd start with that.
I'd defer to Sully and some of our smarter armorers to give you additional advice. I was going to write up my personal TTP on buffers, but I figured BCM is smarter on their stuff than I am.
