Nerf Vulcan Blueprint How Do I Fix My Nerf Vulcan?

How do I fix my Nerf Vulcan? - nerf vulcan blueprint

I have a problem. My friend and I were surrounded by a Vulcan nerve to my other friend from school and various other nonsense ambush. After firing two shots on goal, piston, which usually is found in the course and did not draw the gun. The manual says something, but does nothing. I want the Vulcan? or is there a way to solve this problem?