The correct term is Pea Shooter . The plastic spheres are ideal for a pea shooter but maybe too small for best use in a typical soda straw hence the use of a smaller diameter pen tube.
I’ll be forced to do a test. My lawn is littered with the small green spheres fire by “the boys” who seem to have semiautomatic repeaters with which they have wars.
Thanks, I had forgotten the term “pea shooter”.