[b]WARNING: I HAVEN'T HAD MY COFFEE YET SO WHAT I'M ABOUT TO SAY MAY BE WAAAAAAAAAY OFF![/b]
To my way of thinking a single feed 9mm Uzi or Sten magazine would be more reliable in that the cartridge is already in line with the chamber and so the bolt is basically pusing the round straight forward. In a true Colt 9mm system the magazine is a double-feed setup (like a regular 5.56 AR mag) and so when the bolt strips a cartridge from the mag it has to be "bumped" towards the middle in order to align it with the chamber. (I think that's why the "ears" on the feed ramp were so high.) Also, the Oly is a blow-back and so the bolt doesn't actually "lock up" like the 5.56 AR bolt. Instead it has more of a truncated cone shape to the front of the bolt. Again this is where I would think the Oly system would be more reliable because this would work similar to the forcing cone on a revolver, forcing the bullet/cartridge to align center. I know this is kinda' hard to visualize so I'll try and take some close-up shots of the Oly bolt and chamber.
PS - I'm afraid I don't know of anyone here abouts with a 9mm upper in any make. I hope to pick one up some day, but that will be a while unfortunately.
[url=http://www.bren-ten.com][img]http://image1ex.villagephotos.com/1211382.jpg[/img][/url]
[b][i][red]10mm-aholic:[/red][/i][/b] S&W 1006, S&W 610, Colt Delta Gold Cup, T/C Contender, Olympic Arms CAR-97/10mm, Bren Ten SM, Bren Ten SFL, Ruger Buckeye, Glock 20, iAi Javelina, Bren Ten MP, Paraordnance P16.40 LTD 10mm Conversion & S&W 1086