I am a newbie to guns in general, but I want to make sure I am shooting safely (i.e., using the right ammo). I have a S&W Model 640 .357 Magnum and it came with two cylinders. Are there any special considerations to firing .38 bullets through the .357 cylinder? At this point, I'm not even sure if it's safe, and if it is, if I should expect any difficulties or will need to make adjustments of any kind. I'm trying to figure out if I can avoid switching out the cylinder every time I want to use .38 bullets or if using the .357 cylinder for .38's will degrade my accuracy. To date, I have been handling it by switching the cylinder every time.