This is a toy pistol designed for kid's play, it can be taken apart easily by a small screwdriver hidden in the pistol grip, have fun in assembling and disassembling, and also you can shoot if you put suitable springs in it.

The material setting and springs' size are on the image(you can buy springs on Amazon, links below), also the assembly instruction.

See the videos for more details.

There is an assembly video for reference at:

https://www.youtube.com/watch?v=dlYptLqrOb8

not this pistol, but another similar one on Thingiverse, it is free.

https://www.thingiverse.com/thing:4202903