I've had two setups on my rifle. The first setup used an UTG Tri-Rail Barrel Mount. It worked to hold my UTG WeaponLight during night patrols on my farm, but when on the range, the recoil would loosen the screws. Even with blue loctite, the barrel mount would slip loose and flop around.
My WASR 10/63 With UTG Tri-Rail Barrel Mount and Light
My current, and second setup, uses a Magpul Moe Rail sandwiched between the upper and lower handguards. I saw another member on this forum, can't remember the username, which inspired me to go for this streamlined approach. It seems to handle recoil well and holds my flashlight tightly. With the Moe Rail, I'm able to cut some weight down on the front end of the rifle. I like rails, but I prefer to limit the amount of unused rail.
My WASR 10/63 With MagPul Moe Rail Light Setup