First-Son Enterprises used to make them, but no more. I know because I had some. I found out who took over making them and had them saved as a favorite on my PC until my hard drive crashed and I lost everything. If I figure it out, I'll let you know.
As a side note, I called KVAR months ago and asked why they don't make them. The guy said it was a good idea and would bring it up, but I know how these things work. I believe there is a market for them with the millions of mags out there and the need for a quick 922 part.
Pittsburgh Steelers fan till the day I die, and then some.