I've got a Ruger GP-100 4" barrel that I love dearly. It's a .357 magnum so I can also shoot 38 specials (I'm sure you knew that). My question is as follows. With the many different brands and grains of ammo, if you were to compare lets say a 158gr 38 special to a 158gr 357 magnum, what would be the practical difference, if the bullet was the same? I shoot 130gr FMJ 38 specials and 158gr JSP 357 magnums out of it, and there's a noticable difference in kick, but how would the two rounds compare at an even grain count?