Winchester Super Field (WSF) is my new powder for 9mm. I was talking to the owner of Miwall at the booth at the Ventura gun show about a powder in the WST burn rate range for semi-auto and he suggested I try WSF. Great suggestion! At 4.0 gr it gives enough recoil pulse to easily cycle a Sig P229, Ruger SR9c or Ruger LC9. It makes semi-auto shooting very pleasurable; it doesn't feel "squishy" like WST but then it's not the harsh feel of Clays, either. It falls in-between and makes all day shooting practice a breeze. Fun stuff, I'll have to try it in a .45 ACP casing some day.