HK 416 Upper BCG Issues
Page 1 of 3 1 2 3 LastLast
Results 1 to 10 of 22

Thread: HK 416 Upper BCG Issues

  1. #1
    Member
    gunsnmammons's Avatar
    Join Date : Jan 2018
    Location : Texas
    Posts : 59
    Mentioned
    1 Post(s)

    Default HK 416 Upper BCG Issues

    So I’m not sure what’s the deal with my upper. It is a brownells 416 upper and barrel, MR556 bcg and bolt, and 416 buffer and spring. This is sitting on my rock river lower at the moment. The issue i am having is when i pull the charging handle back it gets stuck right at the end of travel. The only way to release the bolt is to remove the rear takedown pin. I have swapped the upper on another lower and it cycles back just fine. I have never had an issue with my rock river lower either. Does anyone have any idea as to why the bolt is hanging up like this? I have looked over and over and nothing is wearing on the bolt. Any help is appreciated.

  2. #2
    HKPRO PREMIUM PARTNER
    kbinmt's Avatar
    Join Date : Feb 2015
    Location : Big Sky Country
    Posts : 2,870
    Mentioned
    79 Post(s)

    Default

    Quote Originally Posted by gunsnmammons View Post
    So Iím not sure whatís the deal with my upper. It is a brownells 416 upper and barrel, MR556 bcg and bolt, and 416 buffer and spring. This is sitting on my rock river lower at the moment. The issue i am having is when i pull the charging handle back it gets stuck right at the end of travel. The only way to release the bolt is to remove the rear takedown pin. I have swapped the upper on another lower and it cycles back just fine. I have never had an issue with my rock river lower either. Does anyone have any idea as to why the bolt is hanging up like this? I have looked over and over and nothing is wearing on the bolt. Any help is appreciated.
    What trigger/hammer is in the RR?

  3. #3
    Member
    gunsnmammons's Avatar
    Join Date : Jan 2018
    Location : Texas
    Posts : 59
    Mentioned
    1 Post(s)

    Default

    What trigger/hammer is in the RR?[/QUOTE]

    It is a colt milspec. You think the trigger is causing the bolt to hang up like this?

  4. Remove Advertisements
    HKPro.com
    Advertisements

  5. #4
    HKPRO PREMIUM PARTNER
    kbinmt's Avatar
    Join Date : Feb 2015
    Location : Big Sky Country
    Posts : 2,870
    Mentioned
    79 Post(s)

    Default

    It is a colt milspec. You think the trigger is causing the bolt to hang up like this?
    Just wanted to make sure you had a milspec hammer

  6. #5
    Junior Member

    Join Date : Jun 2019
    Posts : 23
    Mentioned
    2 Post(s)

    Default

    is the buffer tube on your rock river lower confirmed milspec diameter or is it commercial

  7. #6
    HKPRO PREMIUM PARTNER

    Join Date : Mar 2019
    Posts : 84
    Mentioned
    1 Post(s)

    Default

    I think you have a trigger issue. Thereís a lot posted here about that issue. I donít think Colt triggers are compatible unless maybe full auto. Start here:
    https://www.hkpro.com/forum/hk416-hk...er-groups.html

  8. #7
    Unrepentant HKHolic
    fatmat27's Avatar
    Join Date : Jul 2009
    Location : Arizona
    Posts : 2,451
    Mentioned
    7 Post(s)

    Default

    walking hamer pin?

  9. #8
    HKPRO PREMIUM PARTNER

    Join Date : Dec 2017
    Location : Virginia
    Posts : 430
    Mentioned
    6 Post(s)

    Default HK 416 Upper BCG Issues

    Isnít the Brownells upper a true HK416 which might be incompatible with the MR556 BCG. Doesnít the MR556 BCG have a cut out specifically different than the 416 BCG? Maybe there is something making the MR556 BCG not seat completely and or pull back completely? This might have nothing to do with the issue but I believe the two BCGs are different and MR556 might not fit properly.

    This thread while not completely on the specific subject touches on the idea. Unfortunately for me most of the pictures are blurry, but may come through for you.

    https://www.hkpro.com/forum/hk416-hk...416-upper.html




    Sent from my iPad using Tapatalk
    Last edited by Dbealmear; 01-01-2020 at 12:34 AM.

  10. #9
    HKPRO PREMIUM PARTNER
    kbinmt's Avatar
    Join Date : Feb 2015
    Location : Big Sky Country
    Posts : 2,870
    Mentioned
    79 Post(s)

    Default

    Quote Originally Posted by Dbealmear View Post
    Isn’t the Brownells upper a true HK416 which might be incompatible with the MR556 BCG. Doesn’t the MR556 BCG have a cut out specifically different than the 416 BCG? Maybe there is something making the MR556 BCG not seat completely and or pull back completely? This might have nothing to do with the issue but I believe the two BCGs are different and MR556 might not fit properly.

    This thread while not completely on the specific subject touches on the idea. Unfortunately for me most of the pictures are blurry, but may come through for you.

    https://www.hkpro.com/forum/hk416-hk...416-upper.html




    Sent from my iPad using Tapatalk
    Edit - I'm incorrect.....again

    https://www.hkpro.com/forum/hk416-hk...ml#post3629406
    Last edited by kbinmt; 01-01-2020 at 06:50 PM.

  11. #10
    HKPRO PREMIUM PARTNER

    Join Date : Dec 2017
    Location : Virginia
    Posts : 430
    Mentioned
    6 Post(s)

    Default

    Quote Originally Posted by kbinmt View Post
    The cut out for the tab on the mr555 barrel extension is in the upper receiver. BCG should have no bearing
    Ok. Just a thought.


    Sent from my iPad using Tapatalk

Page 1 of 3 1 2 3 LastLast

Sponsored Links

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts

Search tags for this page

hk416 bcg in mr556 upoer

Click on a term to search for related topics.