Problem with Nerf Maverick?

Whenever I pull the on my nerf maverick, it goes all the way back, and stops when it reaches the end; then when i let go theres a weird click and the shoots back. Then apparently it's like i never ****** it. I cant fire, so i have to repeat process, but then theres the click thing... Everything is in order, springs attached, blah blah blah. Any suggestions?