Buffer Setup for SBR

The #1 community for Gun Owners of the Northeast

Member Benefits:

  • No ad networks!
  • Discuss all aspects of firearm ownership
  • Discuss anti-gun legislation
  • Buy, sell, and trade in the classified section
  • Chat with Local gun shops, ranges, trainers & other businesses
  • Discover free outdoor shooting areas
  • View up to date on firearm-related events
  • Share photos & video with other members
  • ...and so much more!
  • AssMan

    Meh...
    MDS Supporter
    Jan 27, 2011
    16,211
    Somewhere on the James River, VA
    Finally getting around to building one of my SBR lowers. I'm looking for a buffer/spring/extension for this combo and not sure which direction to go?

    Here's the specs thus far:
    - Spikes billet lower and upper
    - BCM BCG
    - BCM Gunfighter CH
    - Ballistic Advantage 10.5" barrel 0.750
    - Geissele MK13 rail 9.5"
    - Geissele Super gas block
    - Spikes Melonited Carbine Gas Tube

    I will probably run this suppressed 50% of the time. Can someone suggest a decent buffer/spring combo as a starting point? I was thinking VLTOR A5 but not sure...

    TIA!
     

    rouchna

    Defund the ATF
    MDS Supporter
    Nov 25, 2009
    5,951
    Virginia
    Finally getting around to building one of my SBR lowers. I'm looking for a buffer/spring/extension for this combo and not sure which direction to go?

    Here's the specs thus far:
    - Spikes billet lower and upper
    - BCM BCG
    - BCM Gunfighter CH
    - Ballistic Advantage 10.5" barrel 0.750
    - Geissele MK13 rail 9.5"
    - Geissele Super gas block
    - Spikes Melonited Carbine Gas Tube

    I will probably run this suppressed 50% of the time. Can someone suggest a decent buffer/spring combo as a starting point? I was thinking VLTOR A5 but not sure...

    TIA!

    I have 4 5.56 SBRs. They all have Mil-Spec springs and H2 buffers. 2 of them are ran suppressed the majority of the time. No issues here.
     

    outrider58

    Eats Bacon Raw
    MDS Supporter
    Jul 29, 2014
    49,810
    Finally getting around to building one of my SBR lowers. I'm looking for a buffer/spring/extension for this combo and not sure which direction to go?

    Here's the specs thus far:
    - Spikes billet lower and upper
    - BCM BCG
    - BCM Gunfighter CH
    - Ballistic Advantage 10.5" barrel 0.750
    - Geissele MK13 rail 9.5"
    - Geissele Super gas block
    - Spikes Melonited Carbine Gas Tube

    I will probably run this suppressed 50% of the time. Can someone suggest a decent buffer/spring combo as a starting point? I was thinking VLTOR A5 but not sure...

    TIA!

    Not a giant fan of the G super gas block. Being as you will be suppressing the gun at times, I would consider an adjustable GB. Your gun will thank you.
     

    dmable44

    Active Member
    Jul 4, 2018
    117
    Sprinco Blue and an H2 buffer is my go to for a well balanced suppresses/unsuppressed setup
     

    woodline

    Ultimate Member
    MDS Supporter
    Jan 8, 2017
    1,947
    When the AR15 was originally developed the barrel length and twist rate, gas system, bcg weight/design, buffer system, locking system cartridge, powder, barrel, chambering, projectile, etc were all designed to work together. All that is a bit daunting to optimize for those of us home builders that are prone to overthinking things.

    I use superlative arms gas blocks, mostly in bleed off mode. Seems to be the best balance of adjusting dwell time and letting excess gas bleed off due to backpressure, too large a gas port, variable ammunition, etc. I can suppress something like my 18" 2 gun rifle without any major changes, but with a shorter barrel rifle I prefer to optimize with the suppressor as part of the system.

    Not sure what size gas port Ballistic Advantage is using for which barrels. In general it is hard to predict what will be optimal for a given setup without a lot more detail and testing. In general a VLTOR A5 with the A5 buffer and an H1 or H2 will get you "good enough", and a Springco Blue + H2 will get you there too. Overall 5.56 ARs are pretty forgiving about being overgassed, so it is probably not a major concern.
     

    daNattyFatty

    Ultimate Member
    Aug 27, 2009
    3,908
    Bel Air, MD
    It’s been a spell since I’ve handled my 11.5” AR......but I believe I have an H3 with sprinco blue, and of course an SLR adjustable.

    Once the gas setting was dialed in, it was dead nuts reliable and pretty soft shooting.


    Sent from my iPhone using Tapatalk Pro
     

    AssMan

    Meh...
    MDS Supporter
    Jan 27, 2011
    16,211
    Somewhere on the James River, VA
    Thanks. Good info. I’ll look into an adjustable. The Geissele Super block came with the rail and has a good reputation so I went with it. I want to get this up and running for a class next month and will probably not run the suppressor for the class.


    Sent from my iPhone using Tapatalk
     

    calicojack

    American Sporting Rifle
    MDS Supporter
    May 29, 2018
    5,348
    Cuba on the Chesapeake
    So for an adjustable gas block, if I am using a carbine length SBR, should my goal be for a lighter or heavier buffer? I can adjust the gas block for either.
     

    woodline

    Ultimate Member
    MDS Supporter
    Jan 8, 2017
    1,947
    So for an adjustable gas block, if I am using a carbine length SBR, should my goal be for a lighter or heavier buffer? I can adjust the gas block for either.
    That depends on what you are doing. You need enough energy for the system to cycle reliably. For a tuned competition rifle that you keep pretty clean, you might want as light as possible, even to the point of getting a light bolt carrier. For a more serious use rifle you might want reliable operation with enough extra oomph to power through a reasonable amount of fouling and foreign objects, while also not overgassing the system to a point that it beats itself to death or unlocks too early. Or gasses you out if you're running suppressed.
     

    outrider58

    Eats Bacon Raw
    MDS Supporter
    Jul 29, 2014
    49,810
    So for an adjustable gas block, if I am using a carbine length SBR, should my goal be for a lighter or heavier buffer? I can adjust the gas block for either.

    A good starting point is start the block low or even closed and gradually add gas til it begins to function-cycle with every shot. Start with only one round in the mag at a time. Shoot/adjust until the bolt locks back every time. Then two rounds at a time. Still locking back on last round? Add two 'clicks'(if you have an SLR GB) and that's usually a good starting point. Remember how many clicks you opened it up from a completely closed gas block so you'll always know where to start from.
     

    calicojack

    American Sporting Rifle
    MDS Supporter
    May 29, 2018
    5,348
    Cuba on the Chesapeake
    A good starting point is start the block low or even closed and gradually add gas til it begins to function-cycle with every shot. Start with only one round in the mag at a time. Shoot/adjust until the bolt locks back every time. Then two rounds at a time. Still locking back on last round? Add two 'clicks'(if you have an SLR GB) and that's usually a good starting point. Remember how many clicks you opened it up from a completely closed gas block so you'll always know where to start from.

    My take away from this informative thread; For a suppressed SBR use an H2 buffer and adjustable gas block and follow the above directions for adjusting. :thumbsup:
     

    AssMan

    Meh...
    MDS Supporter
    Jan 27, 2011
    16,211
    Somewhere on the James River, VA
    Bumping this again...looking for input on the Superlative Arms "Bleed Off" adjustable block? Found one locally today and bought it, but may return it if people have had bad experiences with it.
     

    erwos

    The Hebrew Hammer
    MDS Supporter
    Mar 25, 2009
    13,866
    Rockville, MD
    I use them. I haven't had any issues. You just need to remember that if you want 100% reliability, you've got to open them a click or two further once you find the lock-back point.
     

    AssMan

    Meh...
    MDS Supporter
    Jan 27, 2011
    16,211
    Somewhere on the James River, VA
    I use them. I haven't had any issues. You just need to remember that if you want 100% reliability, you've got to open them a click or two further once you find the lock-back point.


    Thanks. I’ve never used one, I’m guess I should tune it with the suppressor if that’s how I’m running it? I’m actually pretty happy with the recoil and virtually zero gas to the shooter, but the action and mags are absolutely filthy - seriously filthy. I’m hoping that by pushing some gas out of the block, it runs a bit cooler and cleaner. Any issues with heating up or fouling the hand guard?


    Sent from my iPhone using Tapatalk
     

    woodline

    Ultimate Member
    MDS Supporter
    Jan 8, 2017
    1,947
    I have a couple of these. The only SOTAR approved gas block is the SLR Sentry series if I remember correctly. Dead Air recommends the Superlative, especially in bleed off mode. I haven't had problems with either one but Chad always has good reasons for recommending or not recommending something.
     

    Users who are viewing this thread

    Latest posts

    Forum statistics

    Threads
    274,915
    Messages
    7,258,430
    Members
    33,348
    Latest member
    Eric_Hehl

    Latest threads

    Top Bottom