Home AR-15 AR-15 Upper Build Knights Armament URX III 3 BCM

AR-15 Upper Build Knights Armament URX III 3 BCM

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Building an AR-15 upper receiver with the following components.

BCM BFH 14.5″ mid-length barrel
Knight’s Armament URX III Rail
Rainier mil-spec upper receiver
BCM BCG
BCM charging handle
Knight’s Armament Micro Rear sight
Rainier Upper Receiver parts kit

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18 COMMENTS

  1. Sorry I'm late to the party.. I'm building an upper using this URX rail… I'm going with a DD barrel which comes with a pinned gas lo pro gas block. Any issues with yours and your gas block?

  2. Nice Job bro….I used AS 33MS on the barrel/upper receiver interface and Rocksett in the barrel nut/rail interface. For support I didn't have a carry handle and improvised with scope rings and aluminum barstock.

    BTW ….Like your Sunnto Core Watch.

  3. Nice video! My upper build is almost a twin of yours. I used an aero precision upper, KAC URX 3.1, Daniel Defense 14.5 CHF mid length barrel and a surefire mb 556k. The only part I didn't think ahead about was my gas block. I used a Daniel defense MK12 gas block and I had to shave down the bottom of it so it would clear the rail. My upper runs like a champ.

  4. Good video, not very many out there for the KAC rails. I just put a very similar upper together 13.5 URX 3.1 and 14.5 mid length Daniel Defense barrel, pinned and welded a Surefire flash hider so I can run it suppressed. Best and softest shooting shooting upper I own

  5. Very clean video man. You did a good job with the camera angles as well as keeping it very to the point. Very professional video man. I would recommend reading the Army's M4 Armorers Manual TM 9-1005-319-23&P. You did back off the barrel nut once so that was better than nothing.TM 9-1005-319-23&P 3-10 Section D recommends that you condition the threads 3 times. It helps keep it from backing off. Loctite is not usually needed but I understand why you used it on the URX rail. Keep up the good work! There are too many crappy armorers videos so it's nice to see a well filmed one like yours. 

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