Planning out my SBR build, I’d like to start it this summer. Only thing I don’t know is what buffer weight to go with. I plan on adding an Aimpoint T1 Micro in a LaRue mount later on, but right now it’ll just be the iron sights.
Specs, if they matter, are the following. The options for the BCM stock kit are standard, H, H2, and H3 buffers.
Upper:
BCM 11.5" Upper (DD 10" LITE)
BCM Gunfighter CH Mod 4 Latch
BCM Bolt Carrier Group
Troy Folding Front Sight
Troy Folding Rear Sight
Identical BCM upper except for suppressor. I run a RRA 2 Stage trigger with a H2 buffer and Chrome Silicon flat wire spring. 800 rds so far and not a single issue. All suppressed, relubed after first range trip and 400 rds.
So I take it you like it? I was going to go with a 10.5" upper because I plan on suppressing it later on down the road (after I turn 21 and get the money it would take for the can, tax, and mount), but the 11.5" looks great with a 10" rail.
I own two Colt 6933s. I have shot both of them suppressed and non, with ammo ranging from Wolf to Black Hills, and never had a buffer-related malfunction with the stock H buffer and spring that the guns came with.
I will just say up front that my build is not done however, I picked up an H2 and the Spikes ST-T2 for my 12.5 build. I plan on trying both out. Good luck with your build.
CMMG 11.5" Upper on a Spikes Lower. Running a Spikes ST-T2 buffer
and it runs flawless. Lower power .223 ammo ejects about 1-2:00 and the hotter rounds
eject around 3-4:00 on my rifle. Last round with any ammo so far still locks bolt back. Very smooth buffer to have IMHO.
My LMT 10 SBR came from the factory with a standard buffer, about 600-700 rounds no issues.
Department M4 with LMT 10.5" upper runs with an H buffer again no issues with 1,000 rounds.
We had another department M4 with an LMT 10.5" running a standard buffer and a surplus M16 BCG with lots of problems. I suggested a new BCG (before and after the problems) and H buffer. I emailed LMT and they told me to run the heaviest buffer you could run reliably. It has a new LMT FA BCG and the same carbine buffer 600 rounds no issues! I know you will be running an 11.5” mine is in the safe waiting for a BCM SBR lower, just paid for it Saturday and now the wait begins. I just read the extra inch of BBL gets you a 40% increase in dwell time which should make things easier right out of the gate! Here is the link: http://www.ar15.com/forums/topic.html?b=2&f=138&t=174764
Here is a copy of the response from LMT:
“We pretty much run H buffers. Depending on ammunition, if you can run H2 buffers and have the rifle run reliably, I recommend that.”
Gene Swanson
Technical Specialist
Lewis Machine & Tool Co.
1305 West 11th Street
Milan, IL 61264
I was going to go with a 10.5" upper because I plan on suppressing it later on down the road (after I turn 21 and get the money it would take for the can, tax, and mount), but the 11.5" looks great with a 10" rail.