Just a few thoughts.I have a STI Spartan 9mm and it is extremely reliable with Tripp,Wilson or Chip MCCormack mags,all 10 rounders.Ive put about 2K through it and it has never had a feeding malfunction(some extraction failures from a crappy factory extractor,but I cured that with a AFTEC extractor).
9mm 1911s notoriously like the ammo to be loaded long,I load my rounds to 1.165 and Campro and Berrys work just fine.I stick with round nose bullets as I have read that 9mm 1911s can be fussy with flat profiled bullets.
Awhile back I had a (45)STI Trojan which would nose dive all the time,I got a EGW elevated mag catch and this really helped,so this would be a thought as mentioned above.