I own a couple pistols with rails but have never mounted a light on them. I understand, partially, why cops and swat teams would use them. They enter buildings as a group and work as a team to secure the building. Light, if used properly can turn the tables in their favor. But if your intended use of a pistol is as a CCW or home defense, wouldn't a light usually broadcast your position to the intruder/attacker? I would think if i used any light, it would be hand held and separate from the gun so I could hold it at any angle I wanted without it being a beacon for the intruder to "aim here".