The 40 is awesome. I haven't put an optic on it yet, too many other things on the go. I have done tons of chronographing though. Too much to just list it all. The velocity increase is about 50-125fps depending on the load. Not a bad increase in energy considering the weight and high velocity of the different bullets. The recoil is the biggest difference from the 20 for me. Much less snappy, though the 20 is still very controllable IMO.