The rifle was having a failure to fire quite often, it started as what I though was a brake in and oiling issue but it seems to go far beyond that.

The rounds had a light primer strike and the trigger felt spongy. The rounds used are Federal XM193LC1 using Gen3 PMAGs.

I have a factory build Adam Arms Gas Piston upper with a voodoo barrel in 556, with a Spikes lower using a slide fire mil spec buffer tube spring and buffer (it is NOT a bump or slide fire system) using a FosTech echo trigger. It does malfunction in semi and echo mode.

Initial contact with the company they said that it might be the buffer. I weighed it and it is in the H2 range

It looks like there are dents in the neck and a light primer strike. Add that it shows the ejector marks on the fired brass to the unfired not having it. For the H2 buffer it had close to 1000 rounds. The std buffer had about 500 rounds before it was placed in the 5.56 lower and while it had the same rate of failure to fire as the H2 did, I could only find the 1 round in my grass.

I bought this upper complete from a local dealer.

I tried clp and even grease, on the bolt group, polished the chamber. After the last email with Adam from Adam Arms I cleaned it all again and used mpro7.

When I can get more ammunition for the 6.8 and the 5.56, I do have a different manufacturer for the 556 and I am going to try and switch lowers and see if that changes

how either functions.

Fired brass
https://drive.google.com/file/d/0B6A8UfpmWbzYcHlFQTNPSERwbmM/view?usp=drivesdk

https://drive.google.com/file/d/0B6A8UfpmWbzYcUItRFNKZHV0eUk/view?usp=drivesdk

https://drive.google.com/file/d/0B6A8UfpmWbzYc2oxbV8wN3RxeVU/view?usp=drivesdk

https://drive.google.com/file/d/0B6A8UfpmWbzYY1QxMS1tUE9MSlk/view?usp=drivesdk

https://drive.google.com/file/d/0B6A8UfpmWbzYOHJ2X0pUc0t5Um8/view?usp=drivesdk

https://drive.google.com/file/d/0B6A8UfpmWbzYWWJxQXBBS3J4dDQ/view?usp=drivesdk



Failed rounds
https://drive.google.com/file/d/0B6A8UfpmWbzYSmhWb2w3U3huOHc/view?usp=drivesdk

https://drive.google.com/file/d/0B6A8UfpmWbzYUG1NcENwbDdzSHM/view?usp=drivesdk

https://drive.google.com/file/d/0B6A8UfpmWbzYX3FLVFgxZXhKMG8/view?usp=drivesdk

AR parts
https://drive.google.com/file/d/0B6A8UfpmWbzYVnNaQ2xGYjZTaWs/view?usp=drivesdk

https://drive.google.com/file/d/0B6A8UfpmWbzYcW1VR2FwMHJOYmM/view?usp=drivesdk

https://drive.google.com/file/d/0B6A8UfpmWbzYdVlrd3pjblFGZ3M/view?usp=drivesdk

https://drive.google.com/file/d/0B6A8UfpmWbzYTWRaR2dSeWo3MzQ/view?usp=drivesdk

https://drive.google.com/file/d/0B6A8UfpmWbzYYl9CTHVfaVRORFE/view?usp=drivesdk

https://drive.google.com/file/d/0B6A8UfpmWbzYQTJvaGlpUS02RnM/view?usp=drivesdk

https://drive.google.com/file/d/0B6A8UfpmWbzYLUtTQjlmbksxLXM/view?usp=drivesdk

https://drive.google.com/file/d/0B6A8UfpmWbzYa3dfdjRIN1h5VE0/view?usp=drivesdk

https://drive.google.com/file/d/0B6A8UfpmWbzYYkpfUzhVTExSTTQ/view?usp=drivesdk

Please reach out to Adams Arms at [email protected] or [email protected]

-Phil-

I have been back and forth with Adam about the issue.  But looking for other ideas

Is the AA carrier modified for the fostech trigger?

You do need to modify the carrier for the trigger the area was ground using a bench grinder then polished smooth.

did you try a non-Fostech lower?  i.e. a lower that has a conventional trigger?  did the AA upper work with the conventional trigger?  although i know that's not the objective, just trying to help narrow down the issue for troubleshooting.

I was planning on doing that ASAP I needed to get the 556 rounds back. I am going to swap to my 6.8spc lower on to the Adam Arms upper.