This question occured to me while reading comments in another thread but I didn't want to hijack the thread. I have seen several posts mention firing .38 spl ammo in .357 mag revolvers. While I know it can be done, I have been told by a couple gun smiths and dealers that this is not a good practice unless you are going to be using .38 spl exclusively in that gun. I know little about the technical aspect besides what I have been told but these people said .38's will wear a groove (?) in the chamber after time that will cause a problem with future use of .357 ammo. They said if you want to shoot .38's buy a .38 but if you want a .357 only use .357 cartridges. Have I been told wrong?