I just bought my first revolver, a Ruger GP100 Match Champion. Today was the first time I fired it. I ran 50 rounds of 130 gr 38 Special through it and it shot fine. I then moved up to 158 gr .357 Magnum . This had much more punch, which I expected. They I went back to 158 gr 38 Special. This seemed to have recoil in between the two. Why would 158 gr 38 Special be so much different then 158 gr .357 magnum?