As a sort of update. Since we have 9mm ammo coming out our ears, my son installed a Colt 9mm upper we had laying around on both of our Delta Elites (also we put in a 16 lb recoil spring as the springs on the Elites were a bit over much).
Neither one worked (like malfunctions in every mag - failures to eject). We discovered that both Deltas had a pretty aggressive bevel on the ejector so I figure that switching out the ejector will help some in this regard and probably will still work with the 10mm as I also have a 10mm Colt upper that I installed on a Super .38 frame that works just fine. I also have a 10mm barrel that works fine in my Giles B.E. gun converted to .38 Spl. (the rim size is the same).
Odd that I can get a .38 Special to run 100% in a 1911 but I can't make a 9mm work but then I have ran into weird stuff before. By no means do I doubt you guys are not having problems, sometimes guns are individual things (my partner has the same problems, he shot a 9mm G.M. in 3 IDPA national matches using Win. factory ammo...he has never had a match in which he did not have a malfunction yet the thing works 99.5% of the time on the range).
That does not mean I will give up, the 9mm makes a great "sub caliber training device."
Onward,
Jim