I notice that some of the early posts mentioned pressure. Pressure should not be a factor in measureable recoil. The main culprits are velocity and ejecta (although we often state it as velocity and payload). But ejecta also includes powder and wad. Same shot charge, same velocity . . . a lighter powder charge SHOULD reduce recoil. But not likely as much as reducing the shot charge by 1/8 oz or the muzzle velocity by 50 fps.