I've owned a couple of SIG.a couple of Rugers,one S&W and now own a CZ Shadow SP01 in 9mm.4.0gr of HP38/W231 has always been accurate with either my Lee 125RN or Saeco 125TC and were ''quite'' reliable(well, semi-autos are not yet as reliable as revolvers,are they?).
One thing I've found is that since the 9mm operates at quite a high level of pressure(aprox 30KPSI),matching the bullet size to the barrel dimension is quite critical.And I've ran into less problems and more accuracy when I started casting my bullets a little softer so that they'll bump up to appropriate size when those 4gr of HP 38 light up under it.And it doesn't lead my barrel anymore than my 45s.
Qc