Brownells and Midway have been out for months. Any suggestions on who else may carry it?

Call B-Square. Several years ago I lost a screw for one of their M1A mounts...I could not find one until I called B-Square they were very nice on the phone and they sent it to me.
They might not sell direct, but might be able to tell you where to look. Just a suggestion.

I didnt know there was such a critter but now that I know, I gotta get one. They dont list them on their website.