I have decided to go ahead a get a gen4 g19 and several standard mags (just in case) any of this federal legislation actually comes to pass. Question: I have noticed that glock has some different springs in some of its pistols and these springs have numbers. I have seen some g19 at the local gun shop and while inspecting them, I have found them to have springs #3 and #4. Can someone school me quickly on what I need to know about these spring numbers and is there one that I should be looking for. Is this a reliability issue that caused different springs in the same model pistol?