unknown barrel 22LR for AR platform with odd "extractor"

[Yarome]

The gunbroker add post was "AR-22 barrel" from my emailed receipt. Was listed via a auction house stating widower was selling her husbands firearms collection. No details on this and the picture as best I can remember didnt specifically show the ejector. My assumption was it is a "standard" barrel , I bought a cmmg bolt once I wont the auction. there are absolutely no barrel mfg markings or anything that point to anyone.
The nitrating (sp) ont the barrel and the ejector match color. I'm thinking after talking to Tim that what will give it away is this area:
View attachment 1468264

If you do get any further information... I hope you'll follow up with us. The suspense and not knowing is killing me. Who knows! Maybe it's some early prototype variation design from the CMMG history books(??) That would be cool.

 

[HKL26]

If you do get any further information... I hope you'll follow up with us. The suspense and not knowing is killing me. Who knows! Maybe it's some early prototype variation design from the CMMG history books(??) That would be cool.

Will do - The only reason I still have it is due to wanting to know what it is at this point. Already have a dedicated AR22 upper now so only get reminded about this barrel when I'm digging through my pile of parts.

 

[Greenbug]

It is for a Smith & Wesson M&P 15-22 rifle.

 

[Yarome]

It is for a Smith & Wesson M&P 15-22 rifle.

The photo in post #20 isn't a bolt face (which isn't an M&P, anyway)... it's a barrel extension. See the OP photos if you might have more info on it.