I have an early 90's 640 .357 and have used it as a BUG for years. The trigger was a little rough at first and rapid shooting of .357 loads was a bit of a hand full. So I had my gunsmith smooth out the trigger and I had him install an orange insert on the front sight ramp for faster aquisition. He then sent it out for Magnaporting and I changed the grips to a wooden boot type. Needless to say, it is now one of my favorites and a great shooter.