With Conventional recoil springs, all the coils are spaced equally apart, except for the closed ends. They are beneficial when shooting heavy loads where keeping the slide closed as long as possible is desired. Recoil springs fit over your handgun's guide rod and control how the slide functions. In general, heavy loads need heavy springs and lighter loads need lighter springs. There is no hard and fast rule as to how much "spring" a handgun needs. Too light a spring and the handgun opens and closes early and hard, increasing the felt recoil and battering the frame. Too heavy a spring, the slide is hard to open and may not cycle completely, jamming the firearm. Installation requires disassembly and reassembly of the slide.