I have a 9mm AR I built using the CMMG RDB bolt and barrel kit. It had issues with extraction and ejection, and CMMG sent me a replacement extractor and ejector spring. Well, I managed to send the ejector across the garage never to be found again.

Does anyone know if the ejector is the same as a standard 223/556 ejector for AR15s? I have one of those. I reached out to CMMG on phone and email but haven’t heard back yet (I’m sure they are swamped). I’m hoping to reassemble today and was wondering if anyone knew if the 223 ejector was the right part. Thanks!

Yes, the 9mm CMMG RDB ejector is the same as the 556.  The .40SW and .45 use a rounded ejector.

I presume you know the ejector springs are proprietary and although shorter, have thicker coils and are stiffer than any 556 ejector spring I've seen.

In case you haven't seen it some of my documentation here: http://www.c3junkie.com/?page_id=221

http://www.c3junkie.com/?page_id=280

Thank you. That was a great write up, I had not seen it before. The new ejector spring is very long compared to the old one. Guess I will see. I’ve thought it was reliable several times before, as I’ve gotten through 100 or so rounds then it is trouble city again.