close

Privacy guaranteed - Your email is not shared with anyone.

Stupid BCG Question

Discussion in 'Black Rifle Forum' started by dkf, Feb 14, 2013.

  1. dkf

    dkf

    Messages:
    5,627
    Likes Received:
    280
    Joined:
    Aug 6, 2010
    Got my BCM BCG and it comes with a small o-ring. What exactly is it for? A "Crane O-Ring" of the extractor?
     
  2. WoodenPlank

    WoodenPlank Who?

    Messages:
    7,958
    Likes Received:
    6
    Joined:
    May 15, 2010
    Location:
    NW Florida
    Yes, that's the Crane o-ring. If you are having extraction issues (ie: extractor slipping off the rim of the casing too early during cycling) the o-ring gives extra tension on the extractor.
     

  3. F_G

    F_G

    Messages:
    1,108
    Likes Received:
    110
    Joined:
    Jan 11, 2010
    Location:
    Crown King, AZ
    I have 4 BCM BCG's and they came with the "O" ring already installed plus an extra in a small sealed plastic bag, I'm guessing that's a spare they sent along.
     
  4. dkf

    dkf

    Messages:
    5,627
    Likes Received:
    280
    Joined:
    Aug 6, 2010
    So just leave it off unless I have issues? Going in a mid length upper.
     
  5. dkf

    dkf

    Messages:
    5,627
    Likes Received:
    280
    Joined:
    Aug 6, 2010
    Ok. I took the BCG apart to clean and reoil but did not remove the extractor. I'll just hold onto the o-ring.
     
  6. WoodenPlank

    WoodenPlank Who?

    Messages:
    7,958
    Likes Received:
    6
    Joined:
    May 15, 2010
    Location:
    NW Florida
    Yep! :supergrin:
     
  7. fuzzy03cls

    fuzzy03cls

    Messages:
    2,940
    Likes Received:
    95
    Joined:
    Jan 28, 2010
    Location:
    Florida
    None of my BCM's had the o ring pre installed?
    Basically. I added it on a few, & really see no difference other then trying to get the damn pin back into the extractor pin hole. PITA with the o-ring installed.
     
    Last edited: Feb 14, 2013
  8. dkf

    dkf

    Messages:
    5,627
    Likes Received:
    280
    Joined:
    Aug 6, 2010
    Well maybe I will strip the bolt down again and see if the o-ring is installed on it.
     
  9. dkf

    dkf

    Messages:
    5,627
    Likes Received:
    280
    Joined:
    Aug 6, 2010
    Tore the bolt down again. No o-ring from the factory.
     
  10. Warp

    Warp ΜΟΛΩΝ ΛΑΒΕ

    Messages:
    16,650
    Likes Received:
    553
    Joined:
    Jul 31, 2005
    I don't know anybody that uses the o-ring. Hold onto it, but don't worry about it and don't use it unless you have a specific problem that diagnosis indicates use of the o-ring for.
     
  11. samuse

    samuse

    Messages:
    5,375
    Likes Received:
    24
    Joined:
    Jul 30, 2008
    Location:
    South TX
    You'll generally only need it in suppressed SBRs.

    If you have a properly gassed mid length, you don't need it.

    I run nothing but 14.5" and 16" carbines (Colts and 1 BCM) and I've never needed the O-ring.
     
  12. humanguerrilla

    humanguerrilla

    Messages:
    2,735
    Likes Received:
    0
    Joined:
    Jul 25, 2006
    Location:
    the woods
    ......
     
    Last edited: Feb 16, 2013
  13. ottomatic

    ottomatic

    Messages:
    1,716
    Likes Received:
    464
    Joined:
    Oct 15, 2002
    Location:
    SW Tennessee

    That is exactly what I am looking to (eventually) put together. Suddenly I am worried! Please tell me why I am possibly going to have extraction issues. BTW - no full auto and intend on going with an adjustable gasblock.
     
  14. JimD303

    JimD303

    Messages:
    165
    Likes Received:
    0
    Joined:
    Nov 11, 2006
    Location:
    PA
    I use them and recommend them in every configuration. They don't hurt anything and only add extractor tension... nothing wrong with that.
     
  15. samuse

    samuse

    Messages:
    5,375
    Likes Received:
    24
    Joined:
    Jul 30, 2008
    Location:
    South TX
    Suppressed SBRs usually have much higher gas pressure in the chamber during unlocking/extraction. More extractor tension is beneficial because the case is actually being extracted before it fully contracts.
     
  16. samuse

    samuse

    Messages:
    5,375
    Likes Received:
    24
    Joined:
    Jul 30, 2008
    Location:
    South TX
    If you don't need 'em, don't use 'em. The added tension can decrease the life of the extractor and the extractor pin and cause feed and ejection issues if the tension gets excessive enough.

    I like running a black insert and a Colt gold spring in carbines and mids. The O-ring would be ok if you were running a rifle spring and a blue insert in a carbine or mid gas.