Hot Wheels Launcher (auto locking)

Loved the Hot Wheels Launcher and the way the release mechanism worked. The only issue I had was that my 3 year was not able to do understand how to get the piston locked back. Holding it back and pulling the trigger up was kind of advanced for him.

All I did was modify the ramp and the button/trigger to have a recess for a small spring. The spring I used is about 18mm long and a little over 4mm wide. Now all I need to do is push the piston back and the spring pressure on the bottom of the trigger forces it up into place with a satisfying click! My 3 year can load it over and over by himself now.