I have one in my trap gun. As for how well it works I wouldn't begin to guess on the actual foot pounds of recoil reduced but I certainly enjoy shooting 100 plus rounds a day. If recoil is a problem for you and you can afford the $50.00 then go ahead and try one. At the very least the mercury will add weight to the firearm and every ounce helps to reduce felt recoil. They come in a variety of sizes and no gunsmithing is required for installation. Were you inquiring for a rifle or shotgun?