WTS in AL:
SOCOM magazine block to use Unmodified Sten Magazines in an Olympic style 9mm AR-15.
I bought mine here: www.ar15.com/forums/topic.html?b=7&f=24&t=268316&page=1
Full Disclosure: The design flaw in this block is that it grips the Sten Magazine by the bottom of the welded on portion. It's an issue because there can be a fair amount of variance in the size of the parts between magazines, so some may not sit high enough in the magazine well to function 100%. It just depends on your specific Sten Mags.
Since I can't fully vouch for it's reliability, I'm only going to ask $20 shipped for it.