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.
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?
Just wanted to make sure you had a milspec hammerIt is a colt milspec. You think the trigger is causing the bolt to hang up like this?
is the buffer tube on your rock river lower confirmed milspec diameter or is it commercial
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:
walking hamer pin?
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.
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Last edited by Dbealmear; 01-01-2020 at 12:34 AM.
Last edited by kbinmt; 01-01-2020 at 06:50 PM.