Granted I am not the most experienced shooter, I do however understand basic physics. A firearm no mater what the caliber once fired will cause recoil. Restricting recoil will have an effect, it may be directly on the shooter, the target, or the device and peripherals. Restrict a firearm from recoil and there will be problems, either with the overall functionality and accuracy of the firearm or worse the scope and it's internal components. A static device will cause issues. Sand bags and the natural body mass will far out perform any static device. Incorporate a fluid recoil mechanism in the designs and you are gold.