So I have been looking this up online and I see different answers. What is the difference with lets say my Glock 18lb recoil spring vs a 20lb and 22lb? Which one provides less muzzle flip and recoil? Which one prevents the slide from slamming against the pistol as hard? Reason why I ask is my ole lady wants to shoot this .40 because she loves the feel of the grip. She has shot 9mm, 380, 12ga etc but I don't want the snap of the .40 to start making her gun shy. I would buy a 9mm conversion barrel but a recoil spring is about $100 dollars cheaper. Sorry for all the handgun threads but I hardly know anything about handguns. Actually I just started to really get interested in handguns this year. I really do appreciate all the information from everyone!