Tips:

If any of the springs fall off inside the weapon or the weapon's parts you can use the tweezers to grab them.

If your Nerf Elite Strongarm is still not working here is a link to a Reddit post posted by someone who had a similiar problem.Strongarm barrel doesn't rotate

Sometimes during use the barrel will need to be turned(but make sure you do not push it beyond its limits) or you can just jerk the gun to the side.