Rocket Launcher Toy, made more reliable by adding a pair of grooves inside, and two spikes from the center piece to fit in those grooves.
This is a remix of the original from Nakozen@Nakozen :
https://www.printables.com/model/432773-rocket-launcher-toy-print-in-place
See that site for detailed instructions, and to print Ammunition!
The author remixed this model.