Some time ago I was reading a old copy of Gunworld from the late 80’s I think. There was a article in it about this upper you could get to turn your AR 15/M 16 into kind of a pistol/SMG it did not use the buffer tube and  the upper had kind of a Sten look to it, looked fabricated ie. Made from welded parts not machined from a billet. I think the one in the article was 9mm but they where going to make them in other calibers.  
Well what the hell was it and anyone now where I can find more info?
 

BTT

If the top end was a square tube, odds are it was the "ARC" upper conversion... I, for the life of me, can not recall the name of the guy that made them -- he lived in AZ.

There was another version made by a guy also in AZ that had a integrated suppresor and ejected empties "down" the mag well, which worked well for attaching a brass catcher bag.

Sounds like the Olympic Arms OA-93 upper.

No buffer tube sticking out the back.

I kinda like it.

[url=http://www.ar15.com/forums/topic.html?b=3&f=12&t=156512&w=searchPop]Really cool link that really cool Troy mentioned:[/url]