I haven't done it with a revolver, but I've used dot sights on an auto pistol. Works great. It just depends on your intended application and mode of carry. Some of the bigger revolvers come from the factory with scope mounts built in, but Ruger doesn't show any GP100s with scope mounts. Gunsmith?
EOTech has tested their HWS on .454 Casull revolvers with no problems, so the sight's integrity is not an issue.