Basically, to get 9x19 to major PF it requires unsafe pressure levels. For example, to get a PF of 165 from a 115 grn bullet would require 1434 fps. To get an extra 5 PF of insurance to ensure you don't get minored would require 1478 fps. While super, supercomp, and 9x23 can handle this (with supported chambers), 9x19 cannot. I shudder to think what a 170 PF 9x19 load would do to the case in an unsupported or "generously dimensioned" chamber like the Glock.
SF