For revolvers, get a small metal regular round flashlight, two rubber erasers (the square kind) and two velcro straps. Take the erasers, put them inbetween the barrel of the gun and the flashlight, and then strap it on with the velcro. I do this, and also wear a small led headlamp to see the sights, this way, the flashlight lines up with where you are shooting, and provides enough light to see, and then you can see your sights with the headlamp, and be able to have light wherever you look. The drawback is that you can't holster your pistol, unless you have a scoped holster, but it does free your hands.