They mention that the crossbow probably won't use an actual bow mechanism because of the shotgun grip, just an internal spring; and that's a good thing "because elastic wears out". Real bows don't have elastic strings and neither do quality toy bows. The power comes from the arms and it is very possible for Nerf to have the spring force come from the arms. In fact, I think having a pump action would be the ideal way to have an actual crossbow style Nerf blaster. I mean it's that or pulling the string back by hand.