Why do railguns not have screw-on rubbers in the muzzles?
The idea of a single looped rubber makes it more economical to produce and therefore less expensive to the diver. In actual use the extra rubber that goes around the muzzle gives extra drive. In other words, the rubber can be made a little shorter than that of a screw on set up, therefore giving you a longer drive that will give more speed to the spear. These muzzles are also designed to enable the diver to exchange rubbers easily in the water without tools if he is carrying a spare rubber clipped to his float. The length of extra rubber in the head of the muzzle is 10 cm.
