I have one of these on my 1187 trap. It came already installed so I don't know how much it really dampens recoil. It is adjustable by tightening the nut which puts the compression on the spring. All I know is I can now shoot 3 dram 1 1/8 oz loads and not be bothered with a sore shoulder.
Not especially well.....it is designed for guns that already have reduced recoil...gas operated semi autos. The spring is too weak for a break gun....
it will bottom out the instant you fire and you'll still get smacked.
My sons KS5 has a counter coil? It's made by Danuser. It's effective and not too high priced. If the cylinder ever goes bad, they'll shoot you a replacement very quickly for about 50 bucks. The cylinder failed on his after about 8 years and allot of shells. Good Product!