The S&W 686 is a great revolver. I have both .357 and .44 mags. The .357 will serve you well, unless you were in Alaska, or somewhere where you may encounter large bears, then the .44 would be my choice. One advantage over the .44, is that you can practice with .38 spls with .357. Ammo is starting to get costly, so that is a consideration. I have a Ruger SP 101 in .357 that I use for woods carry, and we do have some 350+ black bears, but I'm more concerned about the crackheads, dope fiends and other criminal element lurking about. The Ruger is built like a tank, but not as smooth as my Smiths. I can't comment on the 45 ACP, I don't own one yet.