CC 4mm bullets incompatible to CC 4mm bullets?

[E-Revonut]

Ta_man: I think you need to either go back to health class or maybe you just wrote this wrong. The females don't go into the males. The male ends are the ones that would have the spring to them, the end that is a shaft separated into 4 pieces. The female end is just a hollow cavity. Much like human anatomy!!!

Not writing this to be an a** or anything just don't want people to be confused by what you wrote.