In the white AR-180B upper receiver

A friend of mine sent me a AR-180B upper receiver to look at and study. Here are a series of pictures giving you a more detailed look at it.

This is a right side view. As you can see they were made with out a dust collector flap.


A shot of the under side showing the welded seam.

DSC_5997csClose up of the rear sight stamping.

DSC_5978sA close up of the tig welded area for the front trunnion.

DSC_5977sThis is a series of pictures showing the front of the trunnion



DSC_5982csA couple of shots of the bottom of the trunion





5 comments to In the white AR-180B upper receiver

  • Well this is exciting! Waiting impatiently for the AR16… Very impatiently. :)

  • My research indicates that the AR15 barrel extension was turned down, pressed into the trunion, then pined in place before being be welded into the upper. I have been unable to determine if the pinning part is accurate or not but I do know that if you do not use a reaction wrench to hold the extension when removing the barrel and simply clamp the flats of the receiver, the extension will turn inside the trunion. Without drawings or a 180B trunion by itself, we may never know for sure. Maybe there is a demilled upper floating around somewhere.

    • Chuck

      They were not pinned.
      I am not sure that the AR-15 trunnion was even turn down. I am working on solid models of the two parts to determine if that is the case or not.

  • Michael

    Would this lower receiver fit a original Armalite AR-18 and make it semi auto instead of full auto?

    • Chuck

      It should fit an original receiver it does not have the capability to install a trip sear that would be required for a full auto. This is a semi auto upper receiver only.

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